[issue38863] Improve is_cgi() in http.server
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[issue24764] cgi.FieldStorage can't parse multipart part headers with Content-Length and no filename in Content-Disposition
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[issue21705] cgi.py: Multipart with more than one file is misparsed
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[issue1047397] cgitb failures
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[issue39727] cgi.parse() fatally attempts str.decode when handling multipart/form-data
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[issue10879] cgi memory usage
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[issue9968] Let cgi.FieldStorage have named uploaded file
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[issue41140] cgitb uses the locale encoding for log files
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[issue41139] cgi uses the locale encoding for log files
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[issue27777] cgi.FieldStorage can't parse simple body with Content-Length and no Content-Disposition
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Re: An I connected here?
On 17/07/2020 20:12, J. Pic wrote: And Hollidays ;) Nah, that's next week ;-) Le ven. 17 juil. 2020 à 21:03, Rhodri James a écrit : On 17/07/2020 19:33, Steve wrote: Sorry folks, I really messed that one up. I tried to doctor up a reply to get the address correct but failed to delete enough to own the message... Yeah, don't do that. Just start a new message, otherwise you'll end up with all the threading for the old message thread, irritating those of us who sort by thread so that we aren't chopping and changing subject all the time :-/ My message did not have anything to do with the "Fake News Detect" subject. I posted a request for assistance about a week ago, no response. I also see very little traffic here, less than there used to be. Has something gone wrong with my set up? No, nothing's wrong. I can't answer for anyone else and I can't recall your specific question, but I suspect you were asking about something I know nothing about and wasn't sufficiently intrigued to go find out about. I think there are fewer experts with time lurking around here (and I don't count myself as one of those, TBH). Recent controversies and the attempts to moderate them have probably upset quite a lot of people one way or another. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: An I connected here?
On 17/07/2020 19:33, Steve wrote: Sorry folks, I really messed that one up. I tried to doctor up a reply to get the address correct but failed to delete enough to own the message... Yeah, don't do that. Just start a new message, otherwise you'll end up with all the threading for the old message thread, irritating those of us who sort by thread so that we aren't chopping and changing subject all the time :-/ My message did not have anything to do with the "Fake News Detect" subject. I posted a request for assistance about a week ago, no response. I also see very little traffic here, less than there used to be. Has something gone wrong with my set up? No, nothing's wrong. I can't answer for anyone else and I can't recall your specific question, but I suspect you were asking about something I know nothing about and wasn't sufficiently intrigued to go find out about. I think there are fewer experts with time lurking around here (and I don't count myself as one of those, TBH). Recent controversies and the attempts to moderate them have probably upset quite a lot of people one way or another. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Formal Question to Steering Council (re recent PEP8 changes)
On 04/07/2020 16:38, Random832 wrote: On Fri, Jul 3, 2020, at 08:48, Rhodri James wrote: As I said in my preamble, it doesn't matter whether you believe that is true or think it's utter bollocks. I asked the question to get the Steering Council's opinion, not anyone else's. If you collectively really must rehash the arguments again, please have the decency to do so in a different thread. The idea that the statement was in any way related to one of the authors being named "White" was an *obvious factual mistake* in your post. Nope. It was a factual mistake in someone else's post. I hesitate to say "obvious" because I have in fact known people to genuinely think things like that. It is *still* irrelevant to what was asked of the Steering Council. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: New to python - Just a question
On 03/07/2020 11:09, Daley Okuwa via Python-list wrote:
Please can someone help
Write an algorithm (choose the language you prefer) that given a character
string, for instance {‘c’,’a’,’i’,’o’,’p’,’a’}, will print out the list of
characters appearing at least 2 times. In this specific example, it would
return {‘a’}. Afterwards, comment out the cost in terms of space and time.
The first thing to do with any problem is to break it down into bits.
In the case of Python, writing them out as "pseudo-code" instructions
often helps. In this case you have:
Set up something to count letters with
For each letter in the string:
If we haven't seen this letter before:
Set the counter for the letter to 1
Else:
Add 1 to the counter for the letter
For each counter:
If the count is 2 or more:
Print the letter
Now there are a lot of possible ways to write that, but they mostly come
down to deciding what data structure to use to count letters with. Have
a browse through a tutorial (or the standard library if you are feeling
adventurous) and see what you think might work, then try it.
Write a bash/python script that takes a directory as an argument and output the
total lines of code in *.cpp files recursively.
In bash, what existing commands count things? If you don't know, how
might you find out? Then you have to figure out how to do that for each
*.cpp file in a directory, and add the totals together.
In Python, you can read a file one line at a time, so how to count the
number of lines in a file should be pretty obvious. Figuring out how to
do that for every *.cpp file in a directory will involve looking through
the standard library, or getting a bash script to do it for you :-)
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Re: Formal Question to Steering Council (re recent PEP8 changes)
On 03/07/2020 15:28, Jon Ribbens via Python-list wrote: On 2020-07-03, Rhodri James wrote: On 02/07/2020 23:46, Random832 wrote: On Thu, Jul 2, 2020, at 18:29, Michael Torrie wrote: Come again? I can see no other link in the verbage with the "relics of white supremacy" that she referred to. If there are other links, they should be included in the commit message. I agree with Rhodri that an explanation would be interesting. Far be it from me to demand one. So whatever. It's possible that this wasn't explained clearly enough in the commit message itself (though I would argue it was definitely adequately explained in the ensuing on-list discussion, and wonder how much of that discussion you've actually read), but the point is that the *whole idea* of "standard English" is tied to white supremacy, not any particular standard whether via its authors or otherwise. As I said in my preamble, it doesn't matter whether you believe that is true or think it's utter bollocks. I asked the question to get the Steering Council's opinion, not anyone else's. You don't get to decide whose opinions are offered. But I do get to decide whose opinions are solicited. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Formal Question to Steering Council (re recent PEP8 changes)
On 02/07/2020 23:46, Random832 wrote: On Thu, Jul 2, 2020, at 18:29, Michael Torrie wrote: Come again? I can see no other link in the verbage with the "relics of white supremacy" that she referred to. If there are other links, they should be included in the commit message. I agree with Rhodri that an explanation would be interesting. Far be it from me to demand one. So whatever. It's possible that this wasn't explained clearly enough in the commit message itself (though I would argue it was definitely adequately explained in the ensuing on-list discussion, and wonder how much of that discussion you've actually read), but the point is that the *whole idea* of "standard English" is tied to white supremacy, not any particular standard whether via its authors or otherwise. As I said in my preamble, it doesn't matter whether you believe that is true or think it's utter bollocks. I asked the question to get the Steering Council's opinion, not anyone else's. If you collectively really must rehash the arguments again, please have the decency to do so in a different thread. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Formal Question to Steering Council (re recent PEP8 changes)
On 02/07/2020 18:11, Dieter Maurer wrote: I am no member of the Council. Thus, your questions are not directed to me. **BUT** you made your questions public and thus you are likely prepared to receive public comments. Fortunately you don't answer any of the questions, so I don't need to have an opinion on that :-) The commit message tries to provide the motivation for the change. In my view, it is good to document change motivations and a commit message is not a bad place for that. True. However, the motivation as appeared in the discussions was (approximately) that many people, especially those whose first language is not English, find being given a list of writing guidelines like Strunk and White's "The Elements of Style" intimidating. That's fair enough, though a bit more consideration suggests that many people have exactly the opposite problem. The wording could be amended to reassure both, and I've been contemplating doing so. The political diatribe about the linguistic contribution to white supremacy of standardized English appeared nowhere in the discussion. Had it done so, I suspect Keala would have realised quite quickly that using it would be (and has been) controversial and divisive, the exact opposite of her stated intentions. All of which is quite beside the point for the questions I raised. As I said, it doesn't matter whether you agree with that political opinion raised, disagree with it, or do not give a monkey's, should _any_ political opinion be in the repo? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Formal Question to Steering Council (re recent PEP8 changes)
We've had the requested 24 hour cooling off, and I don't imagine anyone is surprised that the situation remains unchanged. The commit message that caused the controversy is still in the PEP repository, and is still controversial. Whether you think it's the best thing since the last best thing or the biggest load of bollocks since the last biggest load of bollocks is irrelevant. It's there, it espouses a political stance, and by implication the Steering Council support it. Since explicit is better than implicit :-), I would like to formally ask the Steering Council to answer the following questions. 1. Does the Steering Council think political statements have any place in the Python repositories? 2. If so, for the avoidance of doubt does the Steering Council support the statements in commit 0c6427d? (https://github.com/python/peps/commit/0c6427dcec1e98ca0bd46a876a7219ee4a9347f4) 3. If not, what do they intend to do about the above commit? If the answer to question 1 is a qualified yes or no, both follow-up questions apply. If the answer to question 1 is a prevarication, non-answer or silence, people will still draw their own conclusions. I mention this merely to reinforce the idea that these things are still answers as well as hostages to fortune. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Code of Conduct address "hold message"
On 30/06/2020 15:25, Rhodri James wrote: Having just had occasion to use the code of conduct link (conduct...@python.org), I got back the message: Your mail to 'conduct...@python.org' with the subject Is being held until the list moderator can review it for approval. Ah, it looks like the message I was expecting is generated when the moderator actually picks up the complaint, so that's OK. The generic moderation message is still rather off-putting, though. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Code of Conduct address "hold message"
Having just had occasion to use the code of conduct link (conduct...@python.org), I got back the message: Your mail to 'conduct...@python.org' with the subject Is being held until the list moderator can review it for approval. etc. I know this is the standard moderation message, but it seems rather out of place for the CoC address. It's not the least bit reassuring if you feel uncomfortable about making such reports, as some people (myself included) are. If I were emailing a commercial company's complaints line I would expect something more in the nature of Thank you for your email about "". We will deal with it as soon as we can." Plus the usual platitudes about valuing my input and appreciating my custom which don't necessarily apply here ;-/ Any chance of getting the message altered to something a bit more friendly? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Pycharm offers only implementation of an abstract getter but not an abstract setter
On 24/06/2020 22:46, zljubi...@gmail.com wrote: Why Pycharm didn't offer a setter as well as getter? This is a general Python mailing list. If you have specific questions/complaints about PyCharm, they are probably better addressed directly to the makers of PyCharm. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Python-list Digest, Vol 201, Issue 9
On 09/06/2020 18:31, Joseph Jenne via Python-list wrote: On 2020-06-09 09:00, zljubi...@gmail.com wrote: Well the problem that I am facing with is, that I have to establish interface between python and outer system. Original question was about creation of input object (data that I have received from outer system). If I accept recommendation to use "from_" instead of "from", it could work, for processing input, because processing is under my control. However, my process will create output object that I should json serialize and return back to outer system as a response to the input. If I will have "from_" object property instead of "from", I believe that I should write a custom object to json serializer in order to support changing names from "from_" to "from". It should be possible to name it from_ and then insert it into the __dict__ as 'from', although a custom serializer would probably be preferable from a design standpoint. Might it be simpler to use a dict from the start? You could have a dictionary key of "from" without any problems. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Can't download Pygame and Pgzero
On 05/06/2020 11:54, Lily Sararat via Python-list wrote: I have trouble installing the Pygame and Pgzero on Window. I based on the instruction on the "Computer Coding Python Games for Kids" by Carol Vorderman. Nothing works. I tried Python 3.6.2 as describe in the book and the latest version 3.8.3 still encounter on the same problem. I really need to get this sorted so my kid can spend his summer break mastering the coding. Hi there Lily. We aren't Pygame specialists, but we can give it a go. However to do that you're going to need to give us some details. Which version of Windows are you using? What exactly did you do to install Pygame and Pgzero, in order, and what exactly went wrong. Please copy and paste any error messages, don't send screenshots because the mailing list will strip them off and we won't see them. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Friday Finking: Imports, Namespaces, Poisoning, Readability
AFAIKT the "three" are readability, naming conflicts and source location. On 05/06/2020 01:15, DL Neil via Python-list wrote: - how do you like to balance these three (and any other criteria)? Readability is king. Or queen, if you prefer. Anything that damages readability drops dramatically in its desirability. One consequence of that is that I rarely use "import ... as", since as you mentioned, renamed libraries are a rich source of WTF moments. I would use "import numpy as np" (if I ever used numpy) because it seems to be standard, but I wouldn't type "import pygame as pg" despite having used PyGame extensively in the past. I tend to use "from xxx import yy_yy, " when I'm not importing many things from a library and their names are sufficiently obvious. The definitions of "not many" and "sufficiently obvious" are pretty flexible. In particular, I'll list more items as the qualified names get longer, as you noted. Source location is a non-issue; it's trivial to jump to the imports at the top of the file, look it up and jump back again. Or have two buffers viewing the same file; that's a technique I use quite a lot anyway. If I need to know the signature, that's what documentation is for. I would never rename an object I've imported using "as". It's just not worth the inevitable heartache. If that means I have namespace collisions, that's either a vote to use the qualified name or to change the name of whatever I wrote that clashes with it. - is your preference (or selection) influenced by the facilities offered by your favorite editor/IDE? Not really. I'm an EMACS user, so any of the "fancy" IDE handiwork is immediately out. The only reason you need an IDE is if your support tools suck (sorry, Windows users). - does your decision differ according to whether the 'target module' is one of yours, from the PSL, from some third party, corporate, ...? I'm more likely to change my own module to fit :-) - do you prefer PSL's importlib over Python's native import-s, for one of these (or any other) reason? Um, why would I? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Binary Sort on Python List __xor__
On 31/05/2020 18:01, Evan Schalton wrote: I think you're arguing both sides of the argument -- numpy arrays do have a lot of similar, related operations (because numpy uses them internally -- since they're more efficient) which means they're not fringe. I'm advocating that the built-in list class add the efficient, convenience methods -- especially since it wouldn't be overriding other methods, it would be leveraging standard methods that are currently unimplemented Those methods make perfect sense in the bit-twiddling lists that you are using. They make no sense whatsoever for lists like ["The", "quick", "brown", "fox"]. There's a decent purpose for a class implementing the features you want, but I honestly don't think the generic list class is it. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: .dll problem
[Re-ordered because top-posting is evil ]:-) On 29/05/2020 17:38, Souvik Dutta wrote: On Fri, 29 May, 2020, 9:50 pm Preetha M, wrote: Hello. Warm regards from india. I am a kid who is currently learning python. Hope you are doing well. I know that it is not a problem that you can fix but whenever i try to open the software it shows that api-ms-win-crt-runtime-l1-0-0.dll is missing. I tried reinstalling but it is not working. Every application i install shows that something.dll is missing. Please help. Do you have DirectX installed. It must solve the problem. DirectX is highly unlikely to be involved, as you have been told before Souvik. What the OP actually needs is the missing Windows runtime, which can be obtained straightforwardly from Microsoft. Here's the link: https://www.microsoft.com/en-in/download/details.aspx?id=48145 Incidentally, the first link Google turns up when you search for "windows runtime missing" explains what's going on and points to this link. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Behaviour of os.path.join
On 27/05/2020 17:39, BlindAnagram wrote: I believe by attempting to make the directory I send absolute with abspath() and then copying a file to this path. They expected this to copy the file into the directory with its original name but instead it copies it to the file that abspath 'kindly' converts my directory into. I did complain about their lack of knowledge but I also have a right to complain about a function that converts an explicitly specified directory into a file:-) Well, they're getting exactly the behaviour I'd expect them to get (and not getting what they expect). I'm faintly gobsmacked that anyone expects something like that to work. If you want a directory, create it. That's what os.mkdir (and the pathlib equivalent) is for. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Behaviour of os.path.join
On 27/05/2020 16:12, BlindAnagram wrote: I'm sorry that you don't believe me but all I know is how I intend the path to be used. And the os.path functions aren't helpful here when they actually_change_ the meanings of paths on Windows: fp= "C:\\Documents\finance\\" abspath(fp) 'C:\\Documents\\finance' If you believe these 'before' and 'after' paths are the same I can only assume that you don't work on Windows (where one refers to a directory and the other a file without an extension). More accurately, one is not a legal filename but both are legal directory names. I entirely believe that you have a problem, but I'm inclined to think it's of your own making. You seem to have decided how paths work without checking whether the language agrees with you. It doesn't, and hasn't for over a decade without a significant number of complaints (as in I can't remember the last one, and I've been around here for a while -- it's too hot for me to want to go hunt in the archives :-). How are these unexpected extensionless files getting created? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Behaviour of os.path.join
On 27/05/2020 14:41, BlindAnagram wrote: That is true if you know for sure how your path will be used. But if you don't, there is a world of difference between passing the paths 'name' and 'name\\' on for others to use. And in this situation it doesn't help when os.path functions strip the directory separator off. Only if you impose meaning externally, which implies you do know how your path will be used after all. If you want to know whether a given path corresponds to a file or a directory on a filing system, there's no real substitute for looking on the filing system. Anything else is, as you have discovered, error-prone. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Behaviour of os.path.join
On 26/05/2020 18:07, BlindAnagram wrote: On 26/05/2020 17:46, MRAB wrote: On 2020-05-26 16:48, BlindAnagram wrote: On 26/05/2020 16:22, Ben Bacarisse wrote: BlindAnagram writes: I came across an issue that I am wondering whether I should report as an issue. If I have a directory, say: base='C:\\Documents' and I use os.path.join() as follows: join(base, '..\\..\\', 'build', '') It rather defeats the purpose of os.sep if you include it in a part of the path. What you mean is better expressed as join(base, '..', '..', 'build', '') (and base includes it too, but I can't suggest an alternative because I don't know your intent is far as defaults go.) Thanks for your input but while that part of my path may not be to your liking, it works fine and does not seem to be relevant to my concern, which is that join appears to treat os.sep as an absolute path, which it is not. If it starts with the path separator, then it's absolute (well, absolute on that drive). Agreed. I did not think that I needed to add this exception to my comment as I thought from the the context that it would be clear that I was questioning how it worked at the end of a path, not when used at its start. But you aren't talking about the end of the (finished) path, you are talking about the start of the final path component you pass to os.path.join(), "\\". As the documentation says, "If a component is an absolute path, all previous components are thrown away and joining continues from the absolute path component." Since "\\" is an absolute path component, all the previous components are thrown away and you are left with just "\\". -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Behaviour of os.path.join
On 26/05/2020 18:01, BlindAnagram wrote:
On 26/05/2020 17:09, Stefan Ram wrote:
Mats Wichmann writes:
an absolute path is one that starts with the pathname separator.
The Python Library Reference does not use the term
"pathname separator". It uses "directory separator"
(os.sep) and "filename separator" ('/' on Unix).
On Windows:
|>>> import pathlib
|>>> import os
|>>> pathlib.PureWindowsPath('\\').is_absolute()
|False
|>>> pathlib.PureWindowsPath(os.sep).is_absolute()
|False
|>>> pathlib.PureWindowsPath('/').is_absolute()
|False
Thanks, that seems to suggest that there is an issue and that I should
hence submit this as an issue.
It is indeed most curious as to why this obviously absolute path is not
recognised as such :-)
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Re: stderr writting before stdout
On 24/05/2020 05:27, Souvik Dutta wrote: Is there any precedence or priority order by which sys.stderr.write() and sys.stdout.write() works. No. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Strings: double versus single quotes
On 22/05/2020 20:57, Manfred Lotz wrote: I also believe that transferring habits from C, Rust or whatever to Python doesn't make much sense as Python does not distinguish between a character and string from a type perspective. From a logical perspective, you are correct. From the point of view of someone who writes more C code than Python, not having to remember a new set of habits for Python makes life a lot simpler. Chacun à son goût and all that. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: why no camelCase in PEP 8?
On 18/05/2020 22:07, Eli the Bearded wrote: camelCase ->noCamelCase snake_case ->no_snake_case One of those is easier to "grep" for than the other. Eh. A changed case in the one, an extra character in the other; that's pretty much the same difficulty really. I certainly don't find it "hard" to grep for _snake_case. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Python Installation Problem
On 05/05/2020 05:34, Adolf Yoshua Marbun wrote: Dear Python, I am currently learning about Python. First thing first, I need to install the interpreter Python 3.8.2 before I get to the IDE. But, I have problem during running command. The installation was successful. When I try to run the command prompt, typing "python --version", it always shows me an error message as attached below this message. I tried to follow the message (reinstalling the program), but didn't work. I don't know what it is and I have tried few times to solve the problem from the internet. Unfortunately this is a text-only mailing list, and your attachment was stripped off before any of us had the chance to see it. Could you copy and paste the error message into a message, please? Also if you could let us know what operating system you are using, some people may be able to offer more detailed advice. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: python Netcdf and ncdump
On 30/04/2020 18:55, J Conrado wrote: Please, Please can someone explain to me why I have this difference: in Python int16 SST(y, x) and with ncdump -h short SST(y, x) Presumably on your computer a (signed) short integer is a (signed) sixteen bit integer. That's rather unhelpful of ncdump. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: [RELEASE] Python 3.9.0a6 is now available for testing
On 29/04/2020 20:23, Schachner, Joseph wrote: norm=lambda m: m+(m and(m[-1]!= '\n'and'\n'or' ')or'\n') Parentheses 1 2 1 0 quotes 1 0 1 0 1 01 0 OK I don't see any violation of quoting or parentheses matching. Still trying to figure out what this lambda does. Presumably it's something to do with recognising string prefixes? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: What variable type is returned from Open()?
On 17/04/2020 22:27, dcwhat...@gmail.com wrote: On Friday, April 17, 2020 at 2:11:17 PM UTC-4, Rhodri James wrote: And people wonder why I stick to gdb when at all possible :-) Never worked with it. Is it a debugger for compiled code, i.e. it steps through the executable while displaying the source? Or interpreted code? The GNU project debugger has been around for quite a few decades now. It's a debugger for compiled code, covering about a dozen source languages (I can't be bothered to count at this time of night). It is ridiculously flexible, command-line driven, and most importantly it does what you tell it to do. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: What variable type is returned from Open()?
On 17/04/2020 17:18, dcwhat...@gmail.com wrote: Maybe it isn't true for all IDE's or all languages. (I know SOMEONE will interject here, to argue for the sake of arguing). But when I worked with Groovy in Intellij about 5 years ago, there were times when the IDE was confused, during a debugging sessions. I don't remember the exact details, but that anomaly happened only with DEFed variables ; it didn't happen when the data type was specified. This is a general problem for IDEs, and type information isn't always helpful. The number of times I have had to add useless bits of code to cast something to (uint8_t *) because I want to see the bytes and the IDE will not give up on trying to interpret them for me. And people wonder why I stick to gdb when at all possible :-) -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Floating point problem
On 17/04/2020 12:40, Aakash Jana wrote:
I am running python 3.8 only but my issue is I need more zeroes after my
result.
I want 2/5 = 0.40
But I am only getting 0.4
When you just print or display a floating point number, Python only uses
as many digits as needed if the answer happens to be a (small enough)
exact decimal [*].
>>> foo = 2/5
>>> print(foo)
0.4
If you want the number displayed differently, you have to format it
yourself.
>>> print("{:6f}".format(foo))
0.40
[*]: Since floats are stored internally in the standard IEEE *binary*
format, what constitutes an *exact* decimal may be a little surprising!
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Re: RFC: For Loop Invariants
On 10/04/2020 21:44, Elliott Dehnbostel wrote:
Hello Everyone,
I've also posted this to the python-ideas mailing list, but I thought to
post here as well for a more general audience.
If I've done this incorrectly, please let me know so that I can
improve/revise. I'm new to the Python community and quite enjoy the more
functional features of Python 3, but have I have a peeve about it. I'd like
to propose and discuss the following enhancement to Python 3:
*Consider the following trivial for-loop:*
chars = "abcaaabkjzhbjacvb"
seek = {'a','b','c'}
count = 0for a in chars:
if a in seek:
count += 1
Gross. Twice nested for a simple count.
a) I don't personally think that's gross (apart from the missing
newline, which is just an email artefact I assume).
b) If it's simple like this and you care enough, refactor it as a
comprehension:
count = sum(1 for a in chars if a in seek)
It it's not so simple, neither the comprehension nor your proposal are
going to be as readable as the twice nesting.
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Re: How To Change Package Representation on Shell?
On 01/04/2020 21:22, Abdur-Rahmaan Janhangeer wrote: Greetings list, I have a custom package. import package package '> what do i have to modify from my package to have like package Hi! Do you mean "How do I override the str() or repr() of a module"? I don't think you can. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: How to instantiate a custom Python class inside a C extension?
On 01/04/2020 18:24, Musbur wrote: Am 01.04.2020 15:01 schrieb Rhodri James: I believe you do it in C as you would in Python: you call the Series class! pyseries = PyObject_CallObject((PyObject *)_type, NULL); Well, that dumps core just as everything else I tried. What does work, however, is calling PyType_Ready first: PyType_Ready(_type); pyseries = PyObject_New(Series, _type); PyObject_Init((PyObject *)pyseries, _type);o I don't understand, though, why I have to do that and when. Didn't that already happen when the module was imported? Do I need to do it whenever I create a new instance in C? It should have happened on your module being imported, the line was there in your code. Stick a breakpoint on your module init function and see if it is being called. (The "from thingy import *" always makes me nervous, but it shouldn't be responsible for this.) -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: How to instantiate a custom Python class inside a C extension?
On 01/04/2020 13:42, Musbur wrote: So when created from C, neither the "new" nor the "init" functions are called on the object, only "finalize". No wonder I get segfaults in the real life application. So how is this done right? Here's the C module: I believe you do it in C as you would in Python: you call the Series class! pyseries = PyObject_CallObject((PyObject *)_type, NULL); -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Like c enumeration in python3
On 23/03/2020 02:18, Paulo da Silva wrote: Hi! Suppose a class C. I want something like this: class C: KA=0 KB=1 KC=1 ... Kn=n def __init__ ... ... These constants come from an enum in a .h (header of C file). They are many and may change from time to time. Is there a way to somehow define them from inside __init__ giving for example a list of names as strings? It sounds like what you want is a separate script to process your .h file into a Python module containing an enum, then import that module into your program. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: PEP Idea: Multi-get for lists/tuples and dictionaries (inspired in NumPy)
On 19/03/2020 14:47, Peter J. Holzer wrote: On 2020-03-19 14:24:35 +, Rhodri James wrote: On 19/03/2020 13:00, Peter J. Holzer wrote: It's more compact, especially, if "d" isn't a one-character variable, but an expression: fname, lname = db[people].employee.object.get(pk=1234)[['first_name', 'last_name']] vs. fname = db[people].employee.object.get(pk=1234)['first_name'] lname = db[people].employee.object.get(pk=1234)['last_name'] I have to say I don't think that's more compact at all. It's too wide to be compact. But 83 characters is still more compact than 121 characters. Only if your sole metric is a strict character count. Width matters in perception; two shorter lines are easier to take in than one long line, even if the long line contains fewer characters. Besides, terseness isn't one of Python's objectives. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Why is the program not printing three lines?
On 19/03/2020 13:58, Souvik Dutta wrote:
I should have been more clear
class first():
print("from first")
def second():
print("from second")
first()
When I run the above code the output is
"from first"
(2ND CODE)
class first():
print("from first")
def second():
print("from second")
first.second()
When I run this code the output is
"from first"
"from second"
Thus going by the above logic
class first():
print("from first")
def second():
print("from second")
first()
first.second()
This should have given the following output
from first
from first
from second
Nope. You haven't made your logic clear, but I think you are still
confused about when the code in the class suite is run, and still think
of it as running when an instance is created.
Try running this code:
class first:
print("from first")
Just that. No instantiation, no "first()", nothing else. Just the
class suite itself.
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Re: PEP Idea: Multi-get for lists/tuples and dictionaries (inspired in NumPy)
On 19/03/2020 13:00, Peter J. Holzer wrote: On 2020-03-19 18:22:34 +1300, DL Neil via Python-list wrote: On 19/03/20 3:28 PM, Santiago Basulto wrote: myself missing A LOT features from NumPy, like fancy indexing or boolean arrays. So, has it ever been considered to bake into Python's builtin list and dictionary types functionality inspired by NumPy? I think multi indexing alone would be huge addition. A few examples: [snip]>> I fear that I'm missing your point. How is l[[0, -1]] or fname, lname = d[['first_name', 'last_name']] any better than l[ 0 ], l[ -1 ] or fname = d[ 'first_name' ] lname = d[ 'last_name' ] It's more compact, especially, if "d" isn't a one-character variable, but an expression: fname, lname = db[people].employee.object.get(pk=1234)[['first_name', 'last_name']] vs. fname = db[people].employee.object.get(pk=1234)['first_name'] lname = db[people].employee.object.get(pk=1234)['last_name'] I have to say I don't think that's more compact at all. It's too wide to be compact. I think the second version is more readable (and the third version, where you factored out the common lookup is better still). -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Python question
On 11/03/2020 04:06, Michael Torrie wrote: On 3/10/20 6:49 PM, Souvik Dutta wrote: What about moving on to a social media app completely made in pythoj for python? No thanks. I don't want to be on yet another web forum. I don't need "social media" or a "social media app." Email works exceedingly well for this sort of thing, despite Google's antics. +10 The best response to "This system breaks when I abuse it" is almost always "Well stop abusing it then." -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: encapsulating a global variable
On 25/02/2020 15:06, BlindAnagram wrote: My interest in this stems from wanting to keep the dictionary only available to the function that uses it and also a worry about being called from threaded code. Hiding your dictionary away inside a class or instance isn't going to protect it from threading disasters by itself, though it will make it easier to protect it as you need. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: encapsulating a global variable
On 25/02/2020 15:20, BlindAnagram wrote: class GetIt: seen = dict() def __call__(self, piece): return GetIt.seen[piece] get_it = GetIt() but then you have a global class instance hanging around, which is not actually any better than a global dictionary. This doesn't work for me since get_it(piece) returns the error: builtins.TypeError: get_it() takes no arguments It works for me (pace sticking something in GetIt.seen to avoid getting a KeyError). You aren't muddling up the class name and instance name are you? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: encapsulating a global variable
On 25/02/2020 12:38, BlindAnagram wrote: I would appreciate advice on whether it is possible to avoid the use of a global variable used in a function by encapsulating it in a class without maaking any changes to the call interface (which I cannot change). I have: seen = dict() def get_it(piece): ... return seen[piece] and I am wondering if it is possible to use a class something like class get_it(object): seen = dict() def __call__(piece): return seen[piece] to avoid the global variable. I wouldn't. Calling the class name creates an instance of the class, so won't actually do what you want. You could rewrite the class and create an instance to call instead: class GetIt: seen = dict() def __call__(self, piece): return GetIt.seen[piece] get_it = GetIt() but then you have a global class instance hanging around, which is not actually any better than a global dictionary. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: time.localtime add a parameter for timezone
On 24/02/2020 17:21, Dieter Maurer wrote: qbit wrote at 2020-2-24 05:18 -0800: How about adding a time zone parameter to time.localtime? A offset just like the form: ± hh[:mm[:ss]]. Why should this be necessary? `localtime` returns the time in the "local timezone" -- and the "local timezone" usually does not change between different calls to `localtime`. It can if your calls to localtime() happen either side of a daylight saving time switch. That said, I agree that the timezone doesn't really belong in the output of localtime(). There are a very few occasions when you want it, but more often you should be working in UTC not local time. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Paper Print Help
On 20/02/2020 15:08, Duram wrote: On 19/02/2020 12:17, Rhodri James wrote: On 19/02/2020 14:22, Duram via Python-list wrote: I have a drawing in a .gif file with (a,b) pixels and want to paperprint it in a position (x,y), what would be the code? What have you tried? Nothing, I did not find the module that make to print to the paper Please don't reply to me directly; if it's a question worth asking in public then it's worth answering in public too! OK, let's backtrack a bit. First off, what operating system are you using? Second, do you have this GIF file in any sort of program at the moment, or do you want advice on how to write a program to handle the image? I suspect your question is a bit too specific at the moment, and you have some mistaken assumptions about how images and (most especially) printing work. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Paper Print Help
On 19/02/2020 14:22, Duram via Python-list wrote: I have a drawing in a .gif file with (a,b) pixels and want to paperprint it in a position (x,y), what would be the code? What have you tried? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Technical debt - was Re: datetime seems to be broken WRT timezones (even when you add them)
On 12/02/2020 17:46, Python wrote: On Wed, Feb 12, 2020 at 01:16:03PM +, Rhodri James wrote: On 12/02/2020 00:53, Python wrote: In pretty much every job I've ever worked at, funding work (e.g. with humans to do it) with exactly and precisely the resources required is basically impossible, and management prefers to underfund the work than to overfund it, for cost-savings reasons. This basically means that any non-trivial work you do inevitably will become technical debt s/become/accrue/. The work itself isn't the debt, but its sub-optimality creates debt (or future headaches, if you prefer to think of it that way). I think it's a purely semantic distinction without a practical difference...which was the point I was trying to make. The work is the direct cause of the debt, and at the time it is performed the debt is realized. Without the work, that particular debt is not incurred. You may have eliminated some old debt when the work is done, but your new debt replaces your old debt. Depending on the resources you can devote, that debt may or MAY NOT be less than the other, and sometimes the truth of this can not be discovered until you're already knee deep in it. Here's where the "purely semantic" distinction matters. You are equating the work with the debt, but ignoring the benefit the work presumably brings (otherwise you wouldn't have done it at all). Either you should be rolling it all together or separate both, surely. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Technical debt - was Re: datetime seems to be broken WRT timezones (even when you add them)
On 12/02/2020 00:53, Python wrote: In pretty much every job I've ever worked at, funding work (e.g. with humans to do it) with exactly and precisely the resources required is basically impossible, and management prefers to underfund the work than to overfund it, for cost-savings reasons. This basically means that any non-trivial work you do inevitably will become technical debt s/become/accrue/. The work itself isn't the debt, but its sub-optimality creates debt (or future headaches, if you prefer to think of it that way). IMMEDIATELY, because you will not be given the time to do the job completely in the first place, there will inevitably be bugs which are minor enough to ignore indefinitely, and most likely, in order to meet arbitrary-but-nevertheless-real time constraints you will find yourself obliged to take shortcuts. So conceptually "costs" may be different from "debt" but in practice, you never have one without the other, and "debt" is really just "costs" you haven't paid yet. It's that last bit, "you haven't paid yet", that's the important part. Project managers and accountants alike are very much in favour of putting off paying for things if they can. Sometimes they can be persuaded that the interest on the debt (the extra cost that the code structure imposes on fixing bugs) is too much, and then you get the opportunity to refactor and reduce the overall debt (at a cost, obviously) and the interest you will pay in the future. Sometimes, and this is the bit that bean counters really like, you can get away without paying the debt by ditching the project entirely before the debt is paid off. If you don't want to piss your customers off you need to pay the cost of a replacement project, which will accrue its own technical debt... -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: ERROR in loading data
On 04/02/2020 14:49, laiba.zubai...@gmail.com wrote:
#load the training and testing data, then scale it into the
# range [0, 1]
print("[INFO] loading ADNI data...")
((trainX, trainY), (testX, testY)) = '/content/gdrive/My
Drive/3_Classes/'.loads_data()
trainX = trainX.astype("float") / 255.0
testX = testX.astype("float") / 255.0
# initialize the label names for the ADNI dataset
labelNames = ["outAD", "outCN", "outMCI"]
When i try to run this code I got the following error.
[INFO] loading ADNI data...
---
AttributeErrorTraceback (most recent call last)
in ()
1 print("[INFO] loading ADNI data...")
> 2 ((trainX, trainY), (testX, testY)) = '/content/gdrive/My
Drive/3_Classes/'.loads_data()
3 trainX = trainX.astype("float") / 255.0
4 testX = testX.astype("float") / 255.0
5
So that error is saying that something on line 2 is trying to use an
attribute incorrectly, probably one that doesn't exist (there really
should be more explanatory information in the error, by the way). The
only thing on line 2 that tries to access an attribute is the string
'/content/gdrive/My Drive/3_Classes/', which tries to run the method
loads_data(). Fair enough. A quick test on the interactive command
line or a look in the documents will tell you that strings indeed do not
have a loads_data() method.
I don't know what library you are intending to use, but you need to open
your file with that first.
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Re: when uses time.clock,there are always mistakes
On 03/02/2020 08:04, 石盼 wrote: Hello ! The problem like this: RESTART: Shell >>> import time >>> t = time.clock() Traceback (most recent call last): File "", line 1, in t = time.clock() AttributeError: module 'time' has no attribute 'clock' It is correct, there is no time.clock() function. The documentation is here: https://docs.python.org/3/library/time.html -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Dynamic Data type assignment
On 28/01/2020 12:03, sushma ms wrote: Hi Please find below example and the compiler error, when i'm assigning value dynamically and when we comparing in "if" loop it is throwing compiler error. It should not throw error It absolutely should throw an error. it should assign and act as int why it is thinking as string. Because it is a string. The documentation of "input" is quite explicit about this: input([prompt]) If the prompt argument is present, it is written to standard output without a trailing newline. The function then reads a line from input, converts it to a string (stripping a trailing newline), and returns that. When EOF is read, EOFError is raised. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Friday Finking: Enum by gum
On 24/01/2020 04:26, DL Neil via Python-list wrote: Questions: Have I made proper sense of this? (please don't laugh too much) Um. My basic take on enums is that they provide a convenient namespace to collect together related constants. API flags and opcodes are an obvious example of related constants you would want to keep together, but Python enums can be more complex than that both as structured data and associated functions. Is the above 'interfacing' an appropriate use of enum-s; or is it really 'overkill' or posturing? I think it's an entirely appropriate use of enums. In fact it's pretty much my only use of them. One caveat: when you care about the value of a constant, set it explicitly. Don't rely on auto() to come up with the right number for you, because the documentation really gives you no guarantees. Python v3.6+ brings Flag-enums into the game. These seem better for interface use, as described. Do you prefer them to the 'plain-vanilla' enum, and for what reason? I prefer them when the interface calls for flags, because they behave like flags. I use plain enums when I don't require that behaviour. It's horses for courses, as ever. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: [Python-ideas] Re: Enhancing Zipapp
On 08/01/2020 18:08, many people wrote lots of stuff... Folks, could we pick one list and have the discussion there, rather than on both python-list and python-ideas? Getting *four* copies of Andrew's emails is a tad distracting :-) -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Python, Be Bold!
On 01/01/2020 07:22, Abdur-Rahmaan Janhangeer wrote: -- Self-updating Python distributions Microsoft have proved time and again that this is a really good thing if you want to piss off your customer base. Let's not. -- Distributions which notify about new releases Surely this is the OS's package management system's job? -- Easy compilation to python-specific executable (.pyz is a good candidate) Don't we already have .pyc files? -- More robust native Gui facilities Why is this a core Python issue? GUIs are inherently OS-specific (including those OSes -- or lack of OSes -- which have no graphical interface). -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Python, Be Bold! - The Draft
On 06/01/2020 10:21, Abdur-Rahmaan Janhangeer wrote: Before we begin, we'd like to define the term executable used in the context of this draft. It means an archive that is run by double-clicking. I'm an embedded systems programmer. Congratulations, you have just rendered your draft utterly irrelevant to me and those like me. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Dataset training using Kmeans
On 05/01/2020 12:56, hanan lamaazi wrote: Dear all, I'm actually using the K-means algorithm for clustering, and scikit-learn machine learning in python. when I want to print my "score_accuarcy" using this command print(metrics.accuracy_score(y_test, y_pred)) I get the following error : "Classification metrics can't handle a mix of continuous-multioutput and binary targets" This is probably an exception from metrics.accuracy_score() (you've shorn off too much context for me to be certain). Googling the text gives me no shortage of links; you are far more likely than me to recognise which of them are relevant to your circumstances. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: hexdump module installation error
On 19/12/2019 12:43, tommy yama wrote: Thanks for your quick response i did not expect. I hope you see the error below in my response as i just copy and paste it. "no module named 'hexdump'." In addition, i tried to execute python3 hexdump.py. However, no such file directory. from hexdump import hexdump ModuleNotFoundError: No module named 'hexdump' user@USERnoMacBook-Air LibraBrowser % python3 hexdump.py /usr/local/Cellar/python/3.7.5/Frameworks/Python.framework/Versions/3.7/Resources/Python.app/Contents/MacOS/Python: can't open file 'hexdump.py': [Errno 2] No such file or directory user@USERnoMacBook-Air LibraBrowser % Huh. You've done a "pip3 install hexdump" so I don't know what might be happening here. Sorry. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: hexdump module installation error
On 19/12/2019 11:23, tommy yama wrote: Thanks for your kind response. The error was simply "module Hexdump was not found". Several things: a) Did it really say "module Hexdump was not found"? "hexdump" and "Hexdump" are not the same things; module names are case-sensitive. b) There will have been a whole load more stack trace that might be useful to us. I should have been clearer when I asked you to copy and paste the error that I really meant the whole of the complaint that Python made to you, not just the final error message! Apologies for that. c) I would much prefer it if you didn't top-post, but interleaved your replies like I've done here. I find it hard to follow top-posted messages because they reverse the normal flow of conversation. On Wed, Dec 18, 2019 at 11:39 PM Rhodri James wrote: On 18/12/2019 02:23, tommy yama wrote: Hi, This sounds familiar to somebody? After upgrading my mac OS to Catalina, this persists even after pip3 install hexdump. [image: image.png] I'm afraid this is a text-only mailing list. Your screenshot has been stripped out before any of us saw it. Could you copy and paste (DON'T retype!) the error instead, so we can all read it? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: hexdump module installation error
On 18/12/2019 02:23, tommy yama wrote: Hi, This sounds familiar to somebody? After upgrading my mac OS to Catalina, this persists even after pip3 install hexdump. [image: image.png] I'm afraid this is a text-only mailing list. Your screenshot has been stripped out before any of us saw it. Could you copy and paste (DON'T retype!) the error instead, so we can all read it? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Python3 - How do I import a class from another file
On 11/12/2019 21:32, mus...@posteo.org wrote: On Tue, 10 Dec 2019 14:56:10 -0500 Dennis Lee Bieber wrote: It is called when the language IMPLEMENTATION decides to call it. That time is not specified in the language description/reference manual. Yes it is: "Note: del x doesn’t directly call x.__del__() — the former decrements the reference count for x by one, and the latter is only called when x’s reference count reaches zero." Plain and simple: When the refcount reaches zero. You are assuming that "when" implies "immediately on the occurence." It doesn't. This happens to be the behaviour in CPython, but other implementations vary as Chris has explained several times now. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Python3 - How do I import a class from another file
On 11/12/2019 14:17, Musbur wrote: Am 10.12.2019 22:33 schrieb Paul Moore: You do understand that the reference counting garbage collector is an implementation detail of the CPython implementation *only*, don't you? I don't think that's true. Here's a sentonce from near the top of the "gc" module documentation of Python 3: https://docs.python.org/3/library/gc.html#module-gc "Since the collector supplements the reference counting already used in Python, you can disable the collector if you are sure your program does not create reference cycles." The way I read this is that Python automatically and immediately deletes objects once their refcount goes to zero, and the garbage collector only kicks in case of circular references or other obscure circumstances. The documentation makes no reference to the specific Python implementation, so I believe this is true for CPython as well as others. That's a bug in the documentation, and needs fixing; thanks for pointing it out! It is certainly true that some other Python implementations (Jython for example) do not use reference counting, and disabling the collector may have further-reaching implications for those implementations. I can't speak to the details; the only other implementation I use is Micropython, and I don't use that often enough to have cared about the details of garbage collection beyond noting that it's different to CPython. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Python3 - How do I import a class from another file
On 10/12/2019 19:25, R.Wieser wrote: And to repeat, you have*no* guarantee*at all* in the language spec that this will happen. There is also absolutily no guarantee in those specs that my 'puter will not suddenly transform into a bonzai tree. Should I now expect it to happen ? That's an implementation detail of your computer. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Python3 - How do I import a class from another file
On 10/12/2019 19:00, R.Wieser wrote: MRAB, You merely disabled the mark-and-sweep collector. Nope. Go check the docs on "gc" Yep. Go and check the docs on "gc" *carefully* *plonk* -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Python3 - How do I import a class from another file
On 10/12/2019 17:18, R.Wieser wrote: Chris, Okay. What should happen when you do this? x = 5 del x Should the integer 5 be deleted? Yep. What do you think happens instead ? I've not seen you explain or support anything in that regard, not even now. As it happens, the object that is the integer 5 *isn't* deleted. Once again, you are making assertions based on what you believe to be true, despite having been told otherwise. That's fair enough, but you then give those assertions the weighting of fact. There is a bit of a problem with the above though: It has got zero to do with the __del__ I was talking about. On the contrary, it's exactly the point. You are asserting behaviour that you are not guaranteed. It happens that current versions of CPython conform to your expectations. I have a vague and unreliable recollection that earlier versions didn't. Other Python interpreters may or may not. The language description does not give you that guarantee, so relying on it is at best foolish. I've not seen you point out any mistake with my example (pointing out race contition problems) either. Greg Ewing did: "In that case, it was only working by accident. You were unwittingly relying on the garbage collector to immediately clean up the object as soon as the last reference to it disappeared. That happens to be true currently in CPython (which uses reference counting), but it's not guaranteed by the language." Unless you're referring to some other example. It's a bit hard to tell without the context. Not a smooth move bro. Not a smooth move /at all/ :-( Words fail me. So the language designers couldn't possibly have been so stupid as to do things this way, but you're going to ignore what they did? Actually, they didn't. Did you know you can disable the garbage collector ? Well, you can. Guess what I saw when I disabled it, created a class instance and than deleted it again. Yup, the "print" command I placed in the "__del__" method did actually show output - something that, according to you, could/should never happen ... What you disabled wasn't the garbage collector, it was the garbage collector's periodic background run to detect reference cycles and delete them when they have no external references. The garbage collector itself ran just fine when your instance's reference count reached zero, exactly as everyone has been saying to you. And to repeat, you have *no* guarantee *at all* in the language spec that this will happen. The garbage collector could have waited until it was short of space before deleting the object, for example, which might not happen until your script terminates. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Randomizing Strings In A Microservices World
On 10/12/2019 03:35, Tim Daneliuk wrote: On 12/9/19 8:50 PM, Paul Rubin wrote: Tim Daneliuk writes: - Imagine an environment in which there may be multiple instances of a given microservice written in Python. Decide the maximum number of microservice instances, say 1000. Chop up the 10 digit range into 1000 pieces, so 0..99, 100-199, etc. Give one range to each microservice instance. Then have the microservices give out the numbers sequentially, but treating them as 10 digit numbers and encrypting each one under a 10 digit pseudorandom permutation shared by all the instances. Look up "format preserving encryption" for how to do this. Obvious variants of the above are obvious, and maybe you need some way to hand around chunks of range if some instance gives out more than a million numbers. The problem here is that the services are ephemeral and the number of said services is not fixed. Hm. Normally I'd mash together the MAC address of the interface and the process ID of the service (or whatever individual identifier microservices have -- indeed, whatever microservices *are* :-), but ten digits is a bit few for that. So you want some variant of Paul's approach. * I assume there are a number of machines providing these services. Give them unique numbers -- I'm guessing three digits should be enough for that, but you know your own setup better. How you assign those numbers is up to you; a config file in /etc, a Windows registry key, or some broadcast protocol that the machines use to dynamically configure themselves are all options that spring to mind. * On each machine, something must spin up services when they are needed. That something will be in a position to assign a unique number (within an individual machine) to each service. So do that, using whatever digits you have left after the unique machine number. * Mash these two numbers into a single ten digit identifier. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Regarding problem in python 3.8.0 installation
On 08/12/2019 18:08, alok singh wrote: Sir, My system is windows 7 SP1 32-bit . after installing python in my system,when i try to launch it using command prompt then a message is shown. I am attaching a screenshot of the following. kindly look seriously into my problem and tell me the solution.. I'm afraid this is a text-only mailing list, so your screenshot has been stripped off before any of us could see it. Please could you copy and paste the text of the error message you receive. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: ImportError: No module named Adafruit_SSD1306 Update
On 05/12/2019 19:30, Rhodri James wrote: On 05/12/2019 18:49, RobH wrote: Update: I did python3 Internet.py and now only get this error: pi@raspberrypi:~/Downloads $ python3 Internet.py File "Internet.py", line 24 font = ImageFont.truetype( 'Minecraftia.ttf', 35) ^ TabError: inconsistent use of tabs and spaces in indentation I cannot see what is wrong, as the text is all lined up with that above and below: The problem will be that you have a mix of tabs and spaces in your indentation. This causes problems because some people don't think that the One True Tab Width is 8 characters ;-) so to them the indentation looks ragged. Worse, when they mix tabs and spaces, code that looks to be at the same indentation level to them looks different to the interpreter. The decision was taken a while ago that Python should put its foot down about this, and demand that we use either all tabs or all spaces for our indentation. That's what you've fallen foul off; there must be a mix of tabs and spaces in that line! Or more likely you've used tabs on that line and spaces elsewhere, or vice versa. I should have remember to say that, sorry. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: ImportError: No module named Adafruit_SSD1306 Update
On 05/12/2019 18:49, RobH wrote: Update: I did python3 Internet.py and now only get this error: pi@raspberrypi:~/Downloads $ python3 Internet.py File "Internet.py", line 24 font = ImageFont.truetype( 'Minecraftia.ttf', 35) ^ TabError: inconsistent use of tabs and spaces in indentation I cannot see what is wrong, as the text is all lined up with that above and below: The problem will be that you have a mix of tabs and spaces in your indentation. This causes problems because some people don't think that the One True Tab Width is 8 characters ;-) so to them the indentation looks ragged. Worse, when they mix tabs and spaces, code that looks to be at the same indentation level to them looks different to the interpreter. The decision was taken a while ago that Python should put its foot down about this, and demand that we use either all tabs or all spaces for our indentation. That's what you've fallen foul off; there must be a mix of tabs and spaces in that line! -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: nonlocal fails ?
On 14/11/2019 17:11, R.Wieser wrote:
Rhodri,
MyVar is a global here, so nonlocal explicitly doesn't pick it up.
I do not agree with you there (the variable being global). If it where than
I would have been able to alter the variable inside the procedure without
having to resort to a "global" override (an override which is only valid for
the context its used in by the way, not anywhere else)
Than again, that is how it works in a few other languages, so I might have
been poisonned by them.:-)
You have been.
# This is at the top level of a module
# I.e. it's a global variable
my_global_variable = 5
# You can read globals from within a function without declaring them
def show_my_global():
print(my_global_variable)
# If you try setting it, you get a local instead
def fudge_my_global(n):
my_global_variable = n
show_my_global() # prints '5'
fudge_my_global(2)
show_my_global() # prints '5'
# If you read the variable before setting it, you get an exception
def mess_up_my_global(n):
print(my_global_variable)
my_global_variable = n
mess_up_my_global(2) # UnboundLocalError!
# ...because it must be a local because of the assignment, but it
# doesn't have a value at the time print() is called.
# To do it right, declare you want the global from the get go
def love_my_global(n):
global my_global_variable
print("It was ", my_global_variable)
my_global_variable = n
love_my_global(3) # prints 'It was 5'
show_my_global() # prints '3'
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Re: nonlocal fails ?
On 14/11/2019 13:06, R.Wieser wrote: Hello all, I've just tried to use a "nonlocal MyVar" statement in a procedure defenition, but it throws an error saying "Syntax error: no binding for nonlocal 'MyVar' found. According to platform.python_version() I'm running version 3.8.3 Why am I getting that error ? (already googeled ofcourse) Testcode: - - - - - - - - - - - - Def Proc1() nonlocal MyVar MyVar = 5 MyVar = 7 Proc1() print(MyVar) - - - - - - - - - - - - I've also tried moving "MyVar = 7" to the first line, but that doesn't change anything. Using "global MyVar" works.. The Language Reference says (https://docs.python.org/3/reference/simple_stmts.html#the-nonlocal-statement): "The nonlocal statement causes the listed identifiers to refer to previously bound variables in the nearest enclosing scope *excluding globals.*" (my emphasis.) MyVar is a global here, so nonlocal explicitly doesn't pick it up. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Launching a Script on the Linux Platform
On 12/11/2019 18:25, Rob Gaddi wrote: On 11/12/19 10:06 AM, Wildman wrote: What is the best approach for launching a Python GUI program on a Linux platform. The program will be distributed in .deb format. So the .deb will contain a menu file as well as a .desktop file. The post install script will update the system menu. My question is how should the program be executed? Here are two choices for the "command=" entry in the menu file... command="/path/to/program.py" In this case the hash-bang would have to be included in the program script... #!/usr/bin/env python3 The other choice is this... command="python3 /path/to/program.py" (Of course, the Exec command in the .desktop file should match.) Is one method better than the other or does it acutally matter? I will note that without the shebang (and setting the execute bit), the program is only executable from the GUI menu, not the command prompt. I personally start even GUI programs far more often from a prompt. To follow Linux conventions you'd put the shebang, make the file executable, and put the executable somewhere on the PATH. I'd stick to those conventions barring a particular reason not to. Wildman is talking about launching his program from a menu, so putting it on the PATH is unnecessary. It may even be a bad idea, depending on exactly what he's done :-) As to the original question, there shouldn't really be much of a difference. The original idea of the shebang line invoking env, as far I recall, was that you'd get the "proper" system python3 wherever it had been put rather than something random and possibly malicious. I guess that means to go for your first option. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Using Makefiles in Python projects
On 11/11/2019 19:05, Bill Deegan wrote: You could use SCons (native python... ) I could. But I'd have to learn how to first, and particularly for complex cross-platform working that involves learning a lot of stuff I already know how to do in Make. The time investment has never seemed that worthwhile. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Using Makefiles in Python projects
On 11/11/2019 17:55, Thomas Jollans wrote: I'm sure it's possible to write Makefiles that work with both GNU make and NMake, but I imagine it's a rather limiting and thankless enterprise. Is that something you actually do? (Maybe it's great, I really wouldn't know. Do tell!) Trying to work cross-platform with NMake/GNU make is every bit as horrid as you're imagining when you start getting clever, and I haven't tried doing it for years. Generally when I'm working on both Windows and Linux, Cygwin is involved anyway so I just use GNU make and be done with it. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Using Makefiles in Python projects
On 09/11/2019 23:50, Thomas Jollans wrote: On 09/11/2019 21:30, Chris Angelico wrote: On Sun, Nov 10, 2019 at 2:10 AM Thomas Jollans wrote: On 07/11/2019 20:20, Vitaly Potyarkin wrote: What do you think of using Makefiles for automating common chores in Python projects? Like linting, type checking and testing? I've come up with a reusable Makefile for automating virtual environment management in Python projects. I think it can be useful for simplifying the onboarding of new developers (both new to project and new to Python) and for documenting project's development practices. Here it is: - Repo: https://github.com/sio/Makefile.venv - Demo screencast: https://asciinema.org/a/279646 What do you think? Is this useful or I'm just unaware of some tool that abstracts venv chores away better? As others have said, make is a useful tool and many people use it for different purposes in their Python projects. Nothing wrong with that. HOWEVER, at risk of stating the obvious, using Makefiles written for/on *nix systems on Windows is a bit of a hassle. If, for some reason, your software is *nix-only anyway, that's fine. If not, using make means sacrificing some portability. If your software runs on Windows, of you think it might run on Windows in the future, maybe consider writing simple Python scripts for platform-independent tasks rather than makefiles and shell scripts. Are you assuming that every Windows system has Python, but that you can't get make or bash? Because neither half of that is true. I've happily used makefiles on Windows, and these days, bash is as easy to get hold of as Python is. ChrisA That's why I say "a bit of a hassle". You can get a MSYS set up (whether from Git for Windows or otherwise). You can get it to play nice with the right Python installation and the Python scripts you presumably want to call from the Makefile. But all of that is a bit of a hassle. If you've got almost any development environment for Windows, you've got a version of make. I quite like the NMake that comes with Visual Studio, for example, and use it in preference to the IDE when I can. Yes, it's a hassle, but it's a hassle you're going to go through anyway. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Syntax Suggestion: Pass Function Definition as Argument
On 07/11/2019 13:36, Stephen Waldron wrote:
This is how it is at the moment, however it may be more agreeable, especially
if that is the only purpose of the function, for python users to be able to
define new functions inside of function calls.
No, not seeing it. Sorry, I don't think "I don't want to use up a
precious, precious name in this namespace" is a good enough reason to do
anything, never mind something with a lot of implicit naming going on.
Suppose you had been good and made a module of your Book example. What
is someone reading your code supposed to make of this?
import books
my_books = [
books.Book("Triplanetary", 'E.E. "Doc" Smith'),
books.Book("Foundation", "Isaac Asimov")
]
books.doToBooks(my_books):
print(book.name, ":", book.author)
then:
if book.name == "Foundation":
print("READ THIS FIRST!")
The name "book" has just appeared out of thin air, and without stopping
and reading the code of your module they will have to guess at what it
is. Now in this case their first guess is probably right, but this is a
toy example and just as easily written with lambdas if you're that
worried about using up names.
-10 from me.
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Re: How execute at least two python files at once when imported?
On 06/11/2019 16:02, Spencer Du wrote: Why is importing modules in parallel bad? To put it as simply as I can: 1. The import mechanism is complicated, even the bits that are user-visible. Fiddling with it has a high chance of going wrong. 2. Multi-threading is less complicated than import, but still requires a lot of careful thought. For example you've asserted that the modules you want to import simultaneously, but you also need to consider the import mechanism itself. Put 1 and 2 together, and multi-threaded import sounds like a nightmare. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: How execute at least two python files at once when imported?
On 06/11/2019 11:42, Rhodri James wrote: On 06/11/2019 09:51, Spencer Du wrote: On Tuesday, 5 November 2019 19:44:46 UTC+1, Rhodri James wrote: On 05/11/2019 18:33, Spencer Du wrote: I want to execute at least two python files at once when imported but I dont know how to do this. Currently I can only import each file one after another but what i want is each file to be imported at the same time. That is a very odd requirement. Why would you want to do this? What exactly does "at the same time" mean here? These are modules/files which are independent of each other and have no dependencies with one another. Because of this I want to run modules all at once. "All at once" still isn't a very meaningful phrase. If you want to import modules in parallel, don't. Not only is it hard work to do, it will come back and bite you. Also posting exactly the same answer word for word four different times isn't a very helpful thing to do. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: How execute at least two python files at once when imported?
On 06/11/2019 09:51, Spencer Du wrote: On Tuesday, 5 November 2019 19:44:46 UTC+1, Rhodri James wrote: On 05/11/2019 18:33, Spencer Du wrote: I want to execute at least two python files at once when imported but I dont know how to do this. Currently I can only import each file one after another but what i want is each file to be imported at the same time. That is a very odd requirement. Why would you want to do this? What exactly does "at the same time" mean here? These are modules/files which are independent of each other and have no dependencies with one another. Because of this I want to run modules all at once. "All at once" still isn't a very meaningful phrase. If you want to import modules in parallel, don't. Not only is it hard work to do, it will come back and bite you. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: How execute at least two python files at once when imported?
On 05/11/2019 18:33, Spencer Du wrote: I want to execute at least two python files at once when imported but I dont know how to do this. Currently I can only import each file one after another but what i want is each file to be imported at the same time. That is a very odd requirement. Why would you want to do this? What exactly does "at the same time" mean here? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: __instancecheck__ metaclasses, how do they work: why do I get True when I tuple, why doesn't print run?
On 04/11/2019 22:23, Peter J. Holzer wrote: On 2019-11-04 14:54:23 +, Rhodri James wrote: On 04/11/2019 14:33, Veek M wrote: __metaclass__ = whatever; # is python2.x syntax But not Python3: see PEP 3115 Doesn't "X is python2.x syntax" imply "X is not python3 syntax"? Not necessarily, the OP might have (and apparently was) assuming that it was also Python3 syntax. Also it gave me an opportunity to point him to the appropriate PEP. That said, we've reached the limits of my knowledge here and I'm bowing out of the discussion. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: __instancecheck__ metaclasses, how do they work: why do I get True when I tuple, why doesn't print run?
On 04/11/2019 14:33, Veek M wrote: Aha. You're trying to fix up the metaclass after the fact, which is not the right way to do it. If you change the class definitions to: __metaclass__ = whatever; # is python2.x syntax But not Python3: see PEP 3115 then you get the prints from MyMeta.__instancecheck__(). The isinstance() still returns True, though, and I don't know why. Then again, your definition of MyMeta is really weird. weird how..? (I'm just trying to figure out what's going on with __instancecheck__ - no further higher purpose :p) example, when we do: isinstance(x, (A, B, C)) you expect from the docs that A.__instancecheck__(cls, x) is passed but x = [] also, B and C.__instancecheck__ is not called when I return False Also if I interchange (Bar, Foo), expecting that Foo.__instancecheck__ will be called, it's completely bypassed That must be what's responsible for the True result. Logically the problem must be to do with your MyzMeta class then. I have no idea what. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: __instancecheck__ metaclasses, how do they work: why do I get True when I tuple, why doesn't print run?
On 04/11/2019 11:30, Veek M wrote:
1. Why do I get True whenever i tuple the
isinstance(f, (Bar, Foo))
(and why don't the print's run)
I'm not very familiar with metaclasses, but I can answer the second part
of your question.
The docs say that you can feed it a tuple and that the results are OR'd
The form using a tuple, isinstance(x, (A, B, ...)), is a shortcut for
isinstance(x, A) or isinstance(x, B) or ... (etc.).
-
which implies that the metaclasses are called for each class?
class MyzMeta(type):
def __instancecheck__(cls, other):
print('MyzzMeta', other)
return 0
class MyMeta(MyzMeta, object):
def __instancecheck__(cls, other):
print('MyMeta')
print(cls, other)
return 0
class Foo(list):
__metaclass__ = MyzMeta
pass
class Miaow(object):
pass
class Bar(Foo, Miaow):
__metaclass__ = MyMeta
pass
Aha. You're trying to fix up the metaclass after the fact, which is not
the right way to do it. If you change the class definitions to:
class Foo(list, metaclass=MyzMeta):
pass
class Bar(Foo, Miaow, metaclass=MyMeta):
pass
then you get the prints from MyMeta.__instancecheck__(). The
isinstance() still returns True, though, and I don't know why. Then
again, your definition of MyMeta is really weird.
f = Foo()
b = Bar()
print(isinstance(f, (Bar, Foo)))
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Re: OOP - iterable class: how to delete one of its objects ?
On 02/11/2019 06:30, R.Wieser wrote: Rhodri, Use weak references. A WeakSet (https://docs.python.org/3/library/weakref.html#weakref.WeakSet) is probably what you want. Most likely!As a fresh freshling in regard to python I was not even aware that a "copy object, but do not increment the reference count" existed.Thank you. Could cause some interresting "the object has disappeared!" problems when you're not carefull with it though ... :-) Yes, it can. That's why you want to create a finalizer to tidy up. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: OOP - iterable class: how to delete one of its objects ?
On 01/11/2019 19:15, R.Wieser wrote:
Hello all,
I've created a class from which I can iterate all its instanciated objects
(using an "instances" list).The problem is that I now cannot seem to
delete an object anymore, AFAIK as a copy of its "self" is still inside the
"instances" list.
Object in question:
- - - - - - - - - - - - - - - -
class TheObject:
instances = []
def __init__(self):
self.instances.append(self)
def __del__(self):
print("Deleted!")
- - - - - - - - - - - - - - - -
The question: How can I keep the class iterable, but still have it delete
itself when asked.
Use weak references. A WeakSet
(https://docs.python.org/3/library/weakref.html#weakref.WeakSet) is
probably what you want.
The idea is that the reference to the instance kept by the WeakSet
doesn't contribute to the reference count. This won't automatically
delete the reference from the WeakSet when the instance goes away,
you'll want to set a finalizer for that, but the documentation covers
what you want to know fairly clearly. Trust me, I was doing exactly
this a week or so ago, and it's pretty straightforward.
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Re: Calculations and Variables
On 01/11/2019 17:07, MRAB wrote:
On 2019-11-01 12:36, Rhodri James wrote:
On 31/10/2019 20:14, MRAB wrote:
On 2019-10-31 18:46, ferzan saglam wrote:
The code below which I have written should print the result of 43.6
with the given values I have included at the end of this question,
but for some odd reason I get the result of 44.44.
bill = (input("Enter the total cost of the meal: \n"))
tip = (input("Enter how much the tip is: \n"))
split = (input("Enter how many people there are: \n"))
Why are there parentheses around the inputs? Have you omitted the
conversion to numbers?
My guess is the OP is using Python2 rather than Python3. So my first
piece of advice would be to switch to Python3 now so you don't have to
re-learn oddities like input(), print() and string handling.
The OP says it prints 44.44.
In Python 2, / does integer division, so it would print 44.00.
Well, it's inconsistent one way or the other. We'll have to wait for
more information.
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Re: Calculations and Variables
On 31/10/2019 20:14, MRAB wrote:
On 2019-10-31 18:46, ferzan saglam wrote:
The code below which I have written should print the result of 43.6
with the given values I have included at the end of this question, but
for some odd reason I get the result of 44.44.
bill = (input("Enter the total cost of the meal: \n"))
tip = (input("Enter how much the tip is: \n"))
split = (input("Enter how many people there are: \n"))
Why are there parentheses around the inputs? Have you omitted the
conversion to numbers?
My guess is the OP is using Python2 rather than Python3. So my first
piece of advice would be to switch to Python3 now so you don't have to
re-learn oddities like input(), print() and string handling.
--
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Re: Black
On 21/10/2019 15:18, lizhollinshe...@gmail.com wrote: What do people think about black? It's the new orange? Seriously, some context would be good. I take it from a quick Google that black is a Python code formatter that makes some frankly rather dubious claims for what it will do to your coding. I'm asking because one of my personal preferences is to use spaces for clarity: If your personal preference is not the same as black's, it looks like you shouldn't use black. Just asking the question indicates that you are intending to fight with it, and that's bound to be a waste of energy. 1. right = mystr[ start : ] black version right=mystr[start:] 2. mtime = time.asctime( time.localtime( info.st_mtime ) ) black version mtime = time.asctime(time.localtime(info.st_mtime)) Is there a reason why PEP8 doesn't like these spaces? All I can offer is my personal opinion that brackets of all sorts are their own spacing, and additional spaces reduce clarity rather than increase it. On the other hand I do put extra spaces around everything other than ":" and ".". But like I said, that's my personal preference. (Which indicates that I too shouldn't consider using black!) -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Instantiating sub-class from super
On 14/10/2019 21:55, DL Neil via Python-list wrote: Is there a technique or pattern for taking a (partially-) populated instance of a class, and re-creating it as an instance of one of its sub-classes? In a medically-oriented situation, we have a Person() class, and start collecting information within an instance (person = Person(), etc). During the data-collection process the person's sex may become obvious, eg few males have become/been pregnant. We could stick with Person() and implement specific methods therein, rather than separate Man and Woman sub-classes, but... It seemed better (at the design-level) to have Man( Person ) and Woman( Person ) sub-classes to contain the pertinent attributes, source more detailed and specific questions, and collect such data; by gender. Knowing a lot of Trans people as I do, may I gently suggest that this solution will find many and varied ways of coming back to bite you? -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Curious about library inclusion
On 15/10/2019 12:38, Antoon Pardon wrote: On 11/10/19 15:48, Rhodri James wrote: On 10/10/2019 12:40, Antoon Pardon wrote: About including piped iterators: http://code.activestate.com/recipes/580625-collection-pipeline-in-python/ On 10/10/19 13:00, Paul Moore wrote: As another measure, look at various other libraries on PyPI and ask yourself why *this* library needs to be in the stdlib more than those others. The answer to that question would be a good start for an argument to include the library. Well my answer would be that this library wouldn't add functionality but rather would allow IMO for a more readable coding style. If you split the work to be done over mulitple generators I find it easier to understand when I read something like: for item in some_file | gen1 | gen2 | gen3: ... than when I read something like: for item in gen3(gen2(gen1(somefile))): ... With my ever-so-reactionary hat on, I have to say I'm the other way round. With "gen3(gen2(gen1(somefile)))" it's pretty obvious what's going on -- nested function or generator calls, probably the latter from the name. With "somefile|gen1|gen2|gen3" I need more context to kick my expectations out of the more common meaning of "|" as "or". Yes, context demands that the "|" in your first example can't actually be an "or". It still causes a moment of logical disconnect (currently a long moment) that throws me out of understanding what your code is doing overall into what this line means in particular. It's exactly like coming across an unusual phrasing or iffy grammar in a piece of writing; you get thrown out of the reading experience by having to concentrate on the individual words. But isn't this just a matter of experience? For example does it still causes a moment of logical disconnect when you see a '+' used for concatenation? For me the use of '|' is very similar to how it is used by unix shells. Would the use of an other operator ease this disconnect for you, maybe '>>', or wouldn't that make a difference? I *could* get used to any syntax, but why should I? We have syntax that works perfectly well already. Making me go to the extra effort of importing shell-style pipes or C++-style streams into my mental construct of Python doesn't really seem necessary. (As it happens, I don't think the use of "+" for concatenation did cause me a moment of disconnection, because it already fitted into my mental model. I do recall that's Perl's choice of "." as the concatenation operator *did* cause me to stop and reevaluate quite a lot. People are weird :-) -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Error: thrift.transport.TTransport.TTransportException: Could not start SASL: b'Error in sasl_client_start (-4) SASL(-4): no mechanism available: Unable t
On 11/10/2019 15:13, Prabakaran Hadoop wrote: Thanks for your reply. Any work around or any other way to achieve from python to prestosql . If there is, it'll be in the GitHub issue I linked to. I just applied Google to your question. -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
Re: Curious about library inclusion
On 10/10/2019 12:40, Antoon Pardon wrote: About including piped iterators: http://code.activestate.com/recipes/580625-collection-pipeline-in-python/ On 10/10/19 13:00, Paul Moore wrote: As another measure, look at various other libraries on PyPI and ask yourself why *this* library needs to be in the stdlib more than those others. The answer to that question would be a good start for an argument to include the library. Well my answer would be that this library wouldn't add functionality but rather would allow IMO for a more readable coding style. If you split the work to be done over mulitple generators I find it easier to understand when I read something like: for item in some_file | gen1 | gen2 | gen3: ... than when I read something like: for item in gen3(gen2(gen1(somefile))): ... With my ever-so-reactionary hat on, I have to say I'm the other way round. With "gen3(gen2(gen1(somefile)))" it's pretty obvious what's going on -- nested function or generator calls, probably the latter from the name. With "somefile|gen1|gen2|gen3" I need more context to kick my expectations out of the more common meaning of "|" as "or". Yes, context demands that the "|" in your first example can't actually be an "or". It still causes a moment of logical disconnect (currently a long moment) that throws me out of understanding what your code is doing overall into what this line means in particular. It's exactly like coming across an unusual phrasing or iffy grammar in a piece of writing; you get thrown out of the reading experience by having to concentrate on the individual words. Heh. Literary criticism as applied to programming. Only in Python... -- Rhodri James *-* Kynesim Ltd -- https://mail.python.org/mailman/listinfo/python-list
