Re: [Tutor] Basic question on spaces
Alexander Quest wrote: As you can see, this is quite rudimentary; I have not discovered any special function that eliminates spaces yet, if such a function exits. There was a thread on this a week or so back. There you will find several suggestions however, in Python 3 the simplest is probably to use print() itself. print takes a couple of optional parameters, one of which defines the separator character, by default a space. You can specify an empty string instead and then hard code your spaces. Try help(print) for more details. The other options include using a format string or string concatenation to create the string you want before you send it to print. HTH, Alan G. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Installing module and running
Hi David, On 19 July 2011 20:34, David Merrick merrick...@gmail.com wrote: Thanks for you help.Its 64 bit windows. What directory would the module go in? Scripts or site-packages in Lib? I have Python 2.6 in C drive but the files I am using are in a directory on d drive. Does the the module have to be in in the same directory as the files that use it? When you install additional packages into Python (for example, the nose package as in your case), they become part of your Python installation. Because of this, you can import them just like you can import any other module that is part of Python already and in some cases they add new scripts/commands that can be run from a command line. Physically what happens during installation is that the .py files (and folders/packages) get put into your Python\Lib folder (for example C:\Python27\Lib on my machine.) As an aside, the reason Python is able to find modules in this folder automatically is that the Python\Lib folder is (by default) one of the folders that Python searches in when it encounters an import statement. Consequently, when you put a python module in the Python\Lib folder, it becomes effectively available to any other Python script you might want to run regardless of where the script being run is physically located. As mentioned previously, Python packages oftentimes also include command line programs to interface with the Python installation, or provide other functionality. Typically such modules/programs are put into the Python\Scripts folder, the idea being that you as a user can then run these programs from there. Unfortunately by default (at least on Windows), the Python\Scripts folder is not on your command line (system) path and so won't be found if you type only the script/command name at the command prompt. Consequently, if you want to use a Python script installed in the Python\Scripts folder, you have to make that the current working directory before running the script or specify the full path to the script, otherwise the system obviously won't know where to find the script to run and will respond with a Bad command or filename response. What you want to do is to add the Python\Scripts folder to your system path, then you'll be able to run these Python scripts/commands as if they're inbuilt operating system commands without having to either be in the Python\Scripts folder or specify the full path to run them. To do this, click on the Start button, right click Computer, click Properties, click Advanced System settings, click Environment variables button below, find the PATH entry in the System variables list and click it to select it, then click Edit below that list, press End to move to the end of the line and append the scripts folder with a semicolon to delimit it from the previous path. In my case I therefore would append (excluding the quotes): ;c:\Python27\Scripts Click OK, OK again, OK again. Now when you open a command prompt any script inside of the Python\Scrtips folder will be directly runnable. Now about Python package installation: By convention if you download a Python package manually, you can manually install it by extracting the package archive, then changing the working directory to the root of extracted package, and then running the setup.py script that is usually included with Python packages, with an install option, e.g.: python setup.py install This does the donkey work to copy the modules of the package into the Python\Lib folder, and Python\Scripts folder, if relevant, plus anything else that might need to be done. You could install your nose package like this, e.g. by downloading it, extracting it, then running the above command in the root of the nose folder. I'd like to reiterate though, that one of the packages that make the installation other Python packages even easier, is the setuptools package, which amongst other things creates the easy_install script under the Python\Scripts folder. What it does, is to allow you to install other Python packages directly from the Python package archive without having to manually download them. Eg once you have setuptools installed and thus have easy_setup available as a command/script (runnable from anywhere if you've updated your system PATH as above), then you can install nose (or any other common package available in the Python package repository) by simply opening a command prompt and issuing: easy_install packagename So in your case you'd enter: easy_install nose That's it! This will then automatically download the nose package from the internet, and install it for you. It really is worth it to install setuptools (or one of the newer variants like pip or distribute...) as this makes your life as a Python developer a lot easier when it comes to getting packages downloaded and installed into your Python environment. Does that give you enough understanding to get you going? Cheers Walter ___
[Tutor] Is the Python 3.2.1 documentation available as a .chm file?
Is the Python 3.2.1 documentation available as a .chm file from Python.org? Thanks, Dick Moores ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Is the Python 3.2.1 documentation available as a .chm file?
Richard D. Moores wrote: Is the Python 3.2.1 documentation available as a .chm file from Python.org? I think you'll need to go to Activestate for that. Alan g ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Is the Python 3.2.1 documentation available as a .chm file?
On Wed, Jul 20, 2011 at 06:58, Flynn, Stephen (L P - IT) steve.fl...@capita.co.uk wrote: Saying that, there's nothing stopping you from taking the html version and compiling your own chm from it. Pretty easy to do. Great! But how? Dick ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Is the Python 3.2.1 documentation available as a .chm file?
On 20 July 2011 15:06, Richard D. Moores rdmoo...@gmail.com wrote: On Wed, Jul 20, 2011 at 06:58, Flynn, Stephen (L P - IT) steve.fl...@capita.co.uk wrote: Saying that, there's nothing stopping you from taking the html version and compiling your own chm from it. Pretty easy to do. Great! But how? Google throws up this as most relevant IMHO: http://msdn.microsoft.com/en-us/library/ms670169%28v=vs.85%29.aspx Google also throws up this (http://chmprocessor.sourceforge.net/) which may be interesting/relevant. W ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Unstable IDLE
Hi I use Python 2.7.2 (v2.7.2:8527427914a2, Jun 11 2011, 15:22:34) on a Macbook Pro (Mac OS X 10.6.7). Whenever I want to open a new window in the IDLE or whenever I work with .py file within the IDLE, it crashes either immediately (in case of opening a new window) or after a short time (in case of opening an existing file). I already installed Python a second time, but this also does not help. Has anybody an idea how to fix this problem? Thanks and all best Timo ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Is the Python 3.2.1 documentation available as a .chm file?
On Wed, Jul 20, 2011 at 07:28, Walter Prins wpr...@gmail.com wrote: On 20 July 2011 15:06, Richard D. Moores rdmoo...@gmail.com wrote: On Wed, Jul 20, 2011 at 06:58, Flynn, Stephen (L P - IT) steve.fl...@capita.co.uk wrote: Saying that, there's nothing stopping you from taking the html version and compiling your own chm from it. Pretty easy to do. Great! But how? Google throws up this as most relevant IMHO: http://msdn.microsoft.com/en-us/library/ms670169%28v=vs.85%29.aspx Sorry, I just can't make sense of that page. Google also throws up this (http://chmprocessor.sourceforge.net/) which may be interesting/relevant. So I downloaded and installed chmProcessor only to find that Only one HTML file can be used as source, and there are many in the Python docs. Dick ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Web Programming
Hi all, I have been reading Head First Pythonhttp://www.headfirstlabs.com/books/hfpython/ since some time now. I am stuck in a chapter on Web Development. Web Development has never been an area of my interest and hence I feel stuck in there. If anyone here has read the book, I wish to know if it's okay to skip that chapter and read further? -- Regards Dharmit Shah http://about.me/dharmit ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Web Programming
If it doesn't interest you, skip it and move on. You can always come back and learn it later, which will be easier anyway, with a more robust background. On Wed, Jul 20, 2011 at 11:22 AM, Dharmit Shah shahdhar...@gmail.comwrote: Hi all, I have been reading Head First Pythonhttp://www.headfirstlabs.com/books/hfpython/ since some time now. I am stuck in a chapter on Web Development. Web Development has never been an area of my interest and hence I feel stuck in there. If anyone here has read the book, I wish to know if it's okay to skip that chapter and read further? -- Regards Dharmit Shah http://about.me/dharmit ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Pyglet for 2.7
Is this out yet? ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Pyglet for 2.7
(on a mac. 2.7 python just in case) ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Is the Python 3.2.1 documentation available as a .chm file?
On Wednesday 2011 July 20 06:41, Richard D. Moores wrote: Is the Python 3.2.1 documentation available as a .chm file from Python.org? http://www.python.org/ftp/python/3.2.1/python321.chm HTH -- I have seen the future and I am not in it. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Pyglet for 2.7
What does their website say? On Wed, Jul 20, 2011 at 10:57 AM, Shwinn Ricci arm...@gmail.com wrote: (on a mac. 2.7 python just in case) ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Is the Python 3.2.1 documentation available as a .chm file?
On Wed, Jul 20, 2011 at 09:04, xDog Walker thud...@gmail.com wrote: On Wednesday 2011 July 20 06:41, Richard D. Moores wrote: Is the Python 3.2.1 documentation available as a .chm file from Python.org? http://www.python.org/ftp/python/3.2.1/python321.chm Did that work for you? It got me a chm file that says everywhere, Navigation to the web page was cancelled. Dick ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Unstable IDLE
On Wed, Jul 20, 2011 at 9:26 AM, Timo Smieszek timo.smies...@daad-alumni.de wrote: Hi I use Python 2.7.2 (v2.7.2:8527427914a2, Jun 11 2011, 15:22:34) on a Macbook Pro (Mac OS X 10.6.7). Whenever I want to open a new window in the IDLE or whenever I work with .py file within the IDLE, it crashes either immediately (in case of opening a new window) or after a short time (in case of opening an existing file). I already installed Python a second time, but this also does not help. Has anybody an idea how to fix this problem? Try launching from the command line - you should be able to open the terminal and type idle at the prompt. You'll probably get some more useful information from the traceback when it crashes. If you copy the last line and search Google for mac python idle crash + line, then it might get you some good information. If not, you could copy/paste the entire traceback here and maybe someone can point you in the right direction. HTH, Wayne ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] questions on encoding
Hi, I am looking for test data with accented and multibyte characters. I have found a good resource that I could use to cobble something together (http://www.inter-locale.com/whitepaper/learn/learn-to-test.html) but I was hoping somebody knows some ready resource. I also have some questions about encoding. In the code below, is there a difference between unicode() and .decode? s = §ÇǼÍÍ x = unicode(s, utf-8) y = s.decode(utf-8) x == y # returns True Also, is it, at least theoretically, possible to mix different encodings in byte strings? I'd say no, unless there are multiple BOMs or so. Not that I'd like to try this, but it'd improve my understanding of this sort of obscure topic. Cheers!! Albert-Jan ~~ All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us? ~~___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] what is 'doubleword alignment'?
--- On Mon, 7/18/11, Kushal Kumaran kushal.kumaran+pyt...@gmail.com wrote: From: Kushal Kumaran kushal.kumaran+pyt...@gmail.com Subject: Re: [Tutor] what is 'doubleword alignment'? To: Walter Prins wpr...@gmail.com Cc: tutor@python.org Date: Monday, July 18, 2011, 8:39 AM On Sun, Jul 17, 2011 at 9:15 PM, Walter Prins wpr...@gmail.com wrote: On 17 July 2011 15:26, Lisi lisi.re...@gmail.com wrote: Sorry to be slow. Blame virtually no sleep last night ;-( But even were the power of two bit correct (and I see subsequently that it is not), how is 18 a power of two? The 18 bytes is a bit of an irrelevance. The point is that if the start of the buffer falls on a dword (double word) alligned memory location then in theory the access should be faster. The term is a little bit ambiguous because strictly speaking different processors have different word sizes. Even so, usually when people speak of double-word alignment, it's often the case that the term word in such a context has its original meaning, e.g. 16 bits. A dword is then 32bits or 4 bytes. A doubleword aligned memory address is, using these assumptions, therefore an address that is divisible by 4. Obviously if the word size is 32bits, then a double word would be 64bits and a doubleword aligned address would need to be divisible by 8. As an aside, this type of optimization is often taken care of by compilers under the hood, and in any case it's generally not something that you'll really be considering as a Python programmer. (If however you were working on one of the Python runtimes or implementations, then you might well be sometimes considering this type of thing, depending on exactly how performance critical what you are working might be and what the runtime was being implemented in.) It's not just about performance. Some hardware simply cannot access data that is not correctly aligned. C programs that indiscriminately cast among pointers to types of different sizes are a pain to port off lenient architectures like x86. If you're writing C code that deals with pointers, you *always* need to keep alignment in mind. -- regards, kushal === Hello, Sorry for the late reply. Thank you all for your replies. I said '18' but I meant '16' (maybe my fingers are too big ;-). The text I put in my original post was from the documentation of a .dll/.so file (programmed in C). It was part of a procedure that reads out data. Each variable is 8 bytes or (for string variables) mutliples of 8 bytes (and each byte is 8 bits). I am using struct.unpack and ctypes to process the data in python. It works now, although I still want to read more about this. Where does the distinction little/big endian enter this story? Thanks again, I appreciate it! Albert-Jan ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] little/big endian was Re: what is 'doubleword alignment'?
Albert-Jan Roskam wrote: and ctypes to process the data in python. It works now, although I still want to read more about this. Where does the distinction little/big endian enter this story? That's to do with which bit in a byte/word is most significant. e.g. is the decimal value 1 stored as 0001 # the one on the right hand nibble or as 0001 # the one on the left hand nibble Now scale that up to word sized numbers... Different CPUs do it differently. I can't recall which is which - I'm sure wikipedia will reveal all! :-) HTH, Alan G. Growing to hate my Netbook keyboard more by the day! And hating my PC repairer even more! ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Homework problem
Hi, I'm trying to make a function that receives text (a string) as an argument and returns the same text (as string), but with 1 added to each word that is a number. I need help getting started. So far, I have: def FindNumbers(a_string): for index, char in enumerate(a_string): if char.isdigit(): a_string[index] = def Test(): sometext = I got 432 when I counted, but Jim got 433 which is a lot foronly 6 cats, or were there 12 cats? FindNumbers(sometext) Test()___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Homework problem
On Wed, Jul 20, 2011 at 2:54 PM, Ken Baclig kbac...@yahoo.com wrote: Hi, I'm trying to make a function that receives text (a string) as an argument and returns the same text (as string), but with 1 added to each word that is a number. I need help getting started. So far, I have: def FindNumbers(a_string): for index, char in enumerate(a_string): if char.isdigit(): a_string[index] = def Test(): sometext = I got 432 when I counted, but Jim got 433 which is a lot foronly 6 cats, or were there 12 cats? FindNumbers(sometext) Test() First of all, don't enumerate() the string; split() it instead - this will give you a list of words instead of characters. Then, look at each item in that list; check to see whether it's numeric - isdigit() works for this. If it _is_ numeric, convert it to an int, add one to it, and turn it back into a string. Join the list back into a string, and you're done. Note: you can step through the items in a list by saying (for example) for word in words: - but if you do it that way you can't modify any of the items. If you need to modify them - by adding 1, for example - you need to refer to them by index instead, and the quickest way to do that is for x in range(len(words)): print words[x]. That was a bunch of broad hints - if you need help putting them together, feel free to ask. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Homework problem
Does this look right? Still a little confused if char.isdigit(): num = int(char) + 1 a_string[index] = str(num) print a_string From: Marc Tompkins marc.tompk...@gmail.com To: Ken Baclig kbac...@yahoo.com Cc: tutor@python.org tutor@python.org Sent: Wednesday, July 20, 2011 3:45 PM Subject: Re: [Tutor] Homework problem On Wed, Jul 20, 2011 at 2:54 PM, Ken Baclig kbac...@yahoo.com wrote: Hi, I'm trying to make a function that receives text (a string) as an argument and returns the same text (as string), but with 1 added to each word that is a number. I need help getting started. So far, I have: def FindNumbers(a_string): for index, char in enumerate(a_string): if char.isdigit(): a_string[index] = def Test(): sometext = I got 432 when I counted, but Jim got 433 which is a lot foronly 6 cats, or were there 12 cats? FindNumbers(sometext) Test() First of all, don't enumerate() the string; split() it instead - this will give you a list of words instead of characters. Then, look at each item in that list; check to see whether it's numeric - isdigit() works for this. If it _is_ numeric, convert it to an int, add one to it, and turn it back into a string. Join the list back into a string, and you're done. Note: you can step through the items in a list by saying (for example) for word in words: - but if you do it that way you can't modify any of the items. If you need to modify them - by adding 1, for example - you need to refer to them by index instead, and the quickest way to do that is for x in range(len(words)): print words[x]. That was a bunch of broad hints - if you need help putting them together, feel free to ask. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Homework problem
Ken Baclig wrote: Does this look right? Still a little confused Nope. Notice that Marc said NOT to operate on characters but to split() the string into a wordlist. Then test for each word in the wordlist to see if it isdigit(). Igf so then convert the word to an int() and add one. Then convert the new int back to a str()and insert back into your wordlist. Finally join() your wordlist with spaces to get your original sentence back. if char.isdigit(): num = int(char) + 1 a_string[index] = str(num) print a_string If you need to modify them - by adding 1, for example - you need to refer to them by index instead, and the quickest way to do that is for x in range(len(words)): print words[x]. Or use the enumerate() function you started with HTH, Alan G. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Homework problem
Ken Baclig wrote: Hi, I'm trying to make a function that receives text (a string) as an argument and returns the same text (as string), but with 1 added to each word that is a number. What counts as a number? In the string: Hello world 1234 ham spam which of these do you expect to get back? Hello world 2345 ham spam # Add one to each digit. Hello world 1235 ham spam # Add one to each number. What about strings without spaces like foo123bar? I'm going to assume that you mean to add 1 to any digit, not just to complete numbers. I need help getting started. So far, I have: def FindNumbers(a_string): for index, char in enumerate(a_string): if char.isdigit(): a_string[index] = This can't work, because strings are immutable. They cannot be changed in place. You have to form a new string. The approach I would take is something like this. Here's a version which doesn't actually add one to each digit, but merely turns any digit into an asterisk. Your job is to make it do what it is supposed to do. def add_one_to_digits(a_string): # Give the function a name that says what it does. It doesn't # just FindNumbers, that name is completely inappropriate. result = [] # Holder to build up a new string. for char in a_string: if char.isdigit(): char = * # Anything else gets passed through unchanged. result.append(char) # Assemble the characters into a string. return ''.join(result) def Test(): sometext = I got 432 when I counted, but Jim got 433 which is a lot foronly 6 cats, or were there 12 cats? FindNumbers(sometext) Test() Test functions should actually test something. Try this instead: def test(): source = (I got 432 when I counted, but Jim got 433 which is a lot for only 6 cats, or were there 12 cats?) expected = (I got 543 when I counted, but Jim got 544 which is a lot for only 7 cats, or were there 23 cats?) actual = add_one_to_digits(source) if actual == expected: print(Test passes!) else: print(Test fails!) print(Expected '%s' % expected) print(but actually got '%s' % actual) By the way, the test case is not very good, because there is one digit which is special compared to the others, and it doesn't get tested. Think about it... out of the 10 possible digits, 9 of them are obvious: 0 - 1 1 - 2 2 - 3 etc. but one digit is not obvious. Can you see which one? So you need to include that digit in the test case, so you know it gets handled correctly. -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] questions on encoding
Albert-Jan Roskam wrote:
Hi,
I am looking for test data with accented and multibyte characters. I have found
a good resource that I could use to cobble something together
(http://www.inter-locale.com/whitepaper/learn/learn-to-test.html) but I was
hoping somebody knows some ready resource.
I also have some questions about encoding. In the code below, is there a
difference between unicode() and .decode?
Not functionality-wise. unicode may be slightly faster, on account of
being a function rather than a method, for small strings. But in Python
3, unicode is gone as no longer needed.
s = §ÇǼÍÍ
x = unicode(s, utf-8)
y = s.decode(utf-8)
x == y # returns True
The fact that this works at all is a fluke, dependent on the settings of
your terminal. If I copy and paste the line
s = §ÇǼÍÍ
into my terminal, with an arbitrarily chosen encoding, I get this:
unicode(s, 'utf-8')
Traceback (most recent call last):
File stdin, line 1, in module
UnicodeDecodeError: 'utf8' codec can't decode byte 0xa7 in position 0:
unexpected code byte
(I get a hint that things are not as they should, because the characters
of s look different too.)
Without knowing what encoding your terminal is set to, it is impossible
to tell what bytes s *actually* includes. But whatever they are, whether
they are valid UTF-8 is a matter of chance.
Also, is it, at least theoretically, possible to mix different encodings in
byte strings? I'd say no, unless there are multiple BOMs or so. Not that I'd
like to try this, but it'd improve my understanding of this sort of obscure
topic.
Of course it is! That gives you a broken file, like taking a file
containing a jpeg and appending it to a file containing an mp3. The
resultant file is neither a well-formed mp3 nor a well-formed jpeg.
Unless you have some way of telling where one part ends and the other
starts, you've just broken your file.
Going back to a terminal with the default encoding (whatever that is!),
I can do this:
s = §ÇǼÍÍ # copy and pasted from your email
# note the chars look different in my terminal and email client!
...
a = unicode(s, 'utf-8') # treat it as UTF-8 bytes
b = unicode(s, 'utf-16') # treat it as UTF-16 bytes
t = a.encode('utf-8') + b.encode('utf-16') # mix them together
t
'\xc2\xa7\xc3\x87\xc3\x87\xc2\xbc\xc3\x8d\xc3\x8d\xff\xfe\xc2\xa7\xc3\x87\xc3\x87\xc2\xbc\xc3\x8d\xc3\x8d'
t.decode('utf-8')
Traceback (most recent call last):
File stdin, line 1, in module
File /usr/lib/python2.5/encodings/utf_8.py, line 16, in decode
return codecs.utf_8_decode(input, errors, True)
UnicodeDecodeError: 'utf8' codec can't decode byte 0xff in position 12:
unexpected code byte
t.decode('utf-16')
u'\ua7c2\u87c3\u87c3\ubcc2\u8dc3\u8dc3\ufeff\ua7c2\u87c3\u87c3\ubcc2\u8dc3\u8dc3'
So the mixed bytes t does *not* make valid utf-8, but it happens to make
valid utf-16. That's an accident of the particular bytes that happened
to be in the string s. There's no guarantee that it will always work,
but even when it does, you rarely get a sensible string of characters.
In the same way, a random chunk of bytes from an mp3 file might, by
chance, happen to make up a valid jpeg file -- but it almost certainly
won't make a nice picture, rather just a blob of random pixels.
--
Steven
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Re: [Tutor] little/big endian was Re: what is 'doubleword alignment'?
On 07/19/2011 05:43 PM, Alan Gauld wrote: Albert-Jan Roskam wrote: and ctypes to process the data in python. It works now, although I still want to read more about this. Where does the distinction little/big endian enter this story? That's to do with which bit in a byte/word is most significant. e.g. is the decimal value 1 stored as 0001 # the one on the right hand nibble or as 0001 # the one on the left hand nibble Now scale that up to word sized numbers... Different CPUs do it differently. I can't recall which is which - I'm sure wikipedia will reveal all! :-) Little-endian is the method used by the Intel processor (such as the Pentium). Big-endian is the system used by most network protocols, as well as the 68000 and many other processors. For our purposes, it's the ordering of the bytes within a 16 or 32 bit number. Little-endian puts the least significant byte first, while big-endian puts the most significant byte first. -- DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Homework problem
The instructions are to add one to each number. So the expected result would be: I got 433 when I counted, but Jim got 434 which is a lot for only 7 cats, or were there 13 cats? From: Steven D'Aprano st...@pearwood.info To: tutor@python.org tutor@python.org Sent: Wednesday, July 20, 2011 6:11 PM Subject: Re: [Tutor] Homework problem Ken Baclig wrote: Hi, I'm trying to make a function that receives text (a string) as an argument and returns the same text (as string), but with 1 added to each word that is a number. What counts as a number? In the string: Hello world 1234 ham spam which of these do you expect to get back? Hello world 2345 ham spam # Add one to each digit. Hello world 1235 ham spam # Add one to each number. What about strings without spaces like foo123bar? I'm going to assume that you mean to add 1 to any digit, not just to complete numbers. I need help getting started. So far, I have: def FindNumbers(a_string): for index, char in enumerate(a_string): if char.isdigit(): a_string[index] = This can't work, because strings are immutable. They cannot be changed in place. You have to form a new string. The approach I would take is something like this. Here's a version which doesn't actually add one to each digit, but merely turns any digit into an asterisk. Your job is to make it do what it is supposed to do. def add_one_to_digits(a_string): # Give the function a name that says what it does. It doesn't # just FindNumbers, that name is completely inappropriate. result = [] # Holder to build up a new string. for char in a_string: if char.isdigit(): char = * # Anything else gets passed through unchanged. result.append(char) # Assemble the characters into a string. return ''.join(result) def Test(): sometext = I got 432 when I counted, but Jim got 433 which is a lot foronly 6 cats, or were there 12 cats? FindNumbers(sometext) Test() Test functions should actually test something. Try this instead: def test(): source = (I got 432 when I counted, but Jim got 433 which is a lot for only 6 cats, or were there 12 cats?) expected = (I got 543 when I counted, but Jim got 544 which is a lot for only 7 cats, or were there 23 cats?) actual = add_one_to_digits(source) if actual == expected: print(Test passes!) else: print(Test fails!) print(Expected '%s' % expected) print(but actually got '%s' % actual) By the way, the test case is not very good, because there is one digit which is special compared to the others, and it doesn't get tested. Think about it... out of the 10 possible digits, 9 of them are obvious: 0 - 1 1 - 2 2 - 3 etc. but one digit is not obvious. Can you see which one? So you need to include that digit in the test case, so you know it gets handled correctly. -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
