Re: [Tutor] Re.findall()
On Thu, 12 Apr 2012 09:06:53 -0700
Michael Lewis wrote:
> Here's the "pattern" portion that I don't understand:
>
> re.findall("[^A-Z]+[A-Z]{3}([a-z])[A-Z]{3}[^A-Z]+"
>
You have 5 different parts here:
1) [^A-Z]+ - this matches one or more non-uppercase characters.
The brackets [] describe a set of wanted characters. A-Z would match
any uppercase character, but the caret ^ at the first position inside
the brackets means to inverse the set (i.e., match any character
not in the set). + means to match at least one of the character(s)
described before.
2) [A-Z]{3} - this matches exactly three uppercase characters.
With the braces {} you can define how many characters should match: {3}
matches exactly 3, {3,} matches at least 3, {,3} matches up to three
and {3,6} matches 3 to 6.
3) ([a-z]) - this matches exactly one lowercase character.
The parens () are used to save the character for later use. (using the
group()/groups()-methods, see the docs).
4) [A-Z]{3} - again matches exactly three uppercase characters.
5) [^A-Z]+ - again matches at least one non-uppercase character.
HTH, Andreas
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Re: [Tutor] python connect() function
sorry, gobject comes from the PyGTK package.
On Thu, Apr 12, 2012 at 6:32 PM, Alan Gauld wrote:
> On 12/04/12 16:42, Pierre Barthelemy wrote:
>
>> Thanks for the fast reply. I went a bit deeper into the code and i found
>> where my problem was. The connect function comes from gobject, and the
>> gobject.connect function accepts extra arguments that are passed to the
>> connected function. So i can solve my problem by:
>>
>> data.connect('new_data_point', analysis_client.update_plot,
>> specific_arguments)
>>
>
> Glad you got it working but what is gobject?
>
> It isn't part of the Python standard library that I recognize
> so presumably you are using some kind of add-in Framework
> or library?
>
> Any questions to the list need to specify what you are
> using, if it's not in the standard library we will be
> pretty much in the dark and unlikely to be able to
> help until you tell us.
>
> --
> Alan G
> Author of the Learn to Program web site
> http://www.alan-g.me.uk/
>
>
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Re: [Tutor] python connect() function
On 12/04/12 16:42, Pierre Barthelemy wrote:
Thanks for the fast reply. I went a bit deeper into the code and i found
where my problem was. The connect function comes from gobject, and the
gobject.connect function accepts extra arguments that are passed to the
connected function. So i can solve my problem by:
data.connect('new_data_point', analysis_client.update_plot, specific_arguments)
Glad you got it working but what is gobject?
It isn't part of the Python standard library that I recognize
so presumably you are using some kind of add-in Framework
or library?
Any questions to the list need to specify what you are
using, if it's not in the standard library we will be
pretty much in the dark and unlikely to be able to
help until you tell us.
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
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Re: [Tutor] Re.findall()
On 12/04/12 15:47, Steven D'Aprano wrote: Regular expressions are like super-charged wildcards. In the DOS or Windows command.com or cmd.exe shell, you can use wildcards * and ? to match any characters, or a single character. In Linux and Macintosh shells, you have the same thing only even more so. Just being picky but from Windows 2000 onwards you can use full regex in the "DOS" command shell too. You need to toggle a registry option I believe but "help cmd" will tell all. File and command completion are likewise available if desired. The Windows command line has most of the stuff Bash has. It's the scripting language that still sucks! (And for that there is WSH or Power Shell) -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] should we use multithreading for multiple clients in socket class
On 12/04/12 12:38, Surya K wrote: I am learning networking and just wrote a primitive client server program.. ... So, I tried to run another client (same code but from different file) but found that its now working. I assume that should be *not working*? A more detailed description of what you did and the result would help diagnose the issue. why its happening, should I use multithreading so that I can handle two clients simultaneously?? It's not strictly necessary if there are no resource conflicts such as two attempts to write to the same file/data structure. But in the general case multi-threading a server (or forking a separate process) is a good idea. However, there is some implicit "threading" takes place in the socket library insofar as each session is given a separate temporary port to communicate over once the connection has been accepted so unless the connections are using conflicting resource it should still work. See the network programming topic in my tutorial for an example and screenshots of two clients talking to one server... -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Re.findall()
>
> mjole...@gmail.com wrote:
> > Hi everyone,
> >
> > I am having trouble understanding re.findall(). I've read through the
> > documentation and looked at at some examples online, but I still don't
> have
> > a clear picture.
> >
> > I am going through pythonchallenge.com and I am on challenge 3. I've
> see.
> > The answer to the problem, but I don't understand the "pattern" portion
> of
> > re.findall().
>
>
> What part don't you understand? Do you understand what a so-called regular
> expression is?
>
Here's the "pattern" portion that I don't understand:
re.findall("[^A-Z]+[A-Z]{3}([a-z])[A-Z]{3}[^A-Z]+"
What is going on here? The ^ means to apply this pattern from what I read.
The first pattern and last pattern are in opposite order, meaning that it
goes from [^A-Z]+[A-Z]{3} to [A-Z]{3}[^A-Z]+ - why does the pattern
flip-flop? The first pattern starts as [^A-Z] but the last pattern end with
[^A-Z]. Why do I need the "+" signs? Also, why does this ([a-z]) need the
parenthesis?
>
> Regular expressions are like super-charged wildcards. In the DOS or Windows
> command.com or cmd.exe shell, you can use wildcards * and ? to match any
> characters, or a single character. In Linux and Macintosh shells, you have
> the
> same thing only even more so.
>
I am familiar with wildcards, but I've mostly used * and nothing else.
>
> Regular expressions are a mini programming language for wildcards. For
> example, 'a.*z' is a pattern that matches any string starting with the
> letter
> 'a' and ending with the letter 'z'.
>
> Here's a more complicated example:
>
> 'm[aeiou]{1,2}n'
>
> This regular expression pattern, or regex, matches the letter 'm',
> followed by
> 1 or 2 vowels ('a', 'e', 'i', 'o', or 'u') in a row, followed by 'n'. So it
> will match "moon" or "mean" or "moan" or "man", but not "mpg" or
> "marvelous"
> or "men".
>
> You can learn more about regexes here:
>
> http://docs.python.org/library/re.html
> http://docs.python.org/howto/regex.html
>
>
> --
> Steven
>
> mjole...@gmail.com
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Re: [Tutor] write list to columns
On 12/04/12 15:32, Mark Lawrence wrote: That's going to be quite awkward to do. Files like to be written one complete line at a time. The normal approach would be to build up the table structure in memory and then write the entire table out in one go. Built-in zip? Or have I missed something? The OP specifically said he wanted to write out one *column* at a time to the file. Then go back and write the next column etc. zip would be one way to build the structure in memory prior to printing, as I suggested. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python connect() function
Thanks for the fast reply. I went a bit deeper into the code and i found
where my problem was. The connect function comes from gobject, and the
gobject.connect function accepts extra arguments that are passed to the
connected function. So i can solve my problem by:
data.connect('new_data_point', analysis_client.update_plot, specific_arguments)
Bests,
Pierre
On Thu, Apr 12, 2012 at 9:21 AM, Peter Otten <__pete...@web.de> wrote:
> Pierre Barthelemy wrote:
>
> > I have a question about event handling and the use of the connect
> > function. I have a data object, that contains a series of signals, one
> > being "new_data_point" .
> >
> > When i want to plot the data, i also connect the "new_data_point" event
> to
> > the function "analysis_client.update_plot". I therefore run the line:
> >
> > data.connect('new_data_point', analysis_client.update_plot)
> >
> > In this case, everytime the data object is updated, i also update the
> > plot.
> >
> >
> > I would like to adapt this code to allow to have several plots, connected
> > to several data objects. I would therefore need to specify, when i
> connect
> > the "update_plot" function, which plots needs to be updated.
> > Is it possible to specify arguments to be used by the connected function
> > when the event occurs ? For instance, is there a way to write something
> > like:
> >
> > data.connect('new_data_point',
> > analysis_client.update_plot(specific_plot_instance))
> >
> > So that when the event occurs, the corresponding plot (and only this one)
> > is updated ?
>
> Like Walter I have no idea what framework or library you are talking about.
> The generic answer is yes: Basically you have to make a new function that
> calls the method with a specifc plot instance.
>
> def update_specific_plot():
>analysis_client.update_plot(specific_plot_instance)
> data.connect("new_data_point", update_specific_plot)
>
> A more elegant and more general version of the above would create the
> helper
> function on the fly using functools.partial():
>
> from functools import partial
>
> data.connect("new_data_point",
>partial(analysis_client.update_plot, specific_plot_instance))
>
>
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Re: [Tutor] Re.findall()
On 12/04/2012 14:53, mjole...@gmail.com wrote: Hi everyone, I am having trouble understanding re.findall(). I've read through the documentation and looked at at some examples online, but I still don't have a clear picture. I am going through pythonchallenge.com and I am on challenge 3. I've see. The answer to the problem, but I don't understand the "pattern" portion of re.findall(). Thanks! Sent from my iPhone ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor Please give us an example of the code that you've tried, what you expect to see and what the actual output from your program was. If an exception occurred please cut and paste the entire exception traceback into this thread. -- Cheers. Mark Lawrence. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Re.findall()
mjole...@gmail.com wrote:
Hi everyone,
I am having trouble understanding re.findall(). I've read through the
documentation and looked at at some examples online, but I still don't have
a clear picture.
I am going through pythonchallenge.com and I am on challenge 3. I've see.
The answer to the problem, but I don't understand the "pattern" portion of
re.findall().
What part don't you understand? Do you understand what a so-called regular
expression is?
Regular expressions are like super-charged wildcards. In the DOS or Windows
command.com or cmd.exe shell, you can use wildcards * and ? to match any
characters, or a single character. In Linux and Macintosh shells, you have the
same thing only even more so.
Regular expressions are a mini programming language for wildcards. For
example, 'a.*z' is a pattern that matches any string starting with the letter
'a' and ending with the letter 'z'.
Here's a more complicated example:
'm[aeiou]{1,2}n'
This regular expression pattern, or regex, matches the letter 'm', followed by
1 or 2 vowels ('a', 'e', 'i', 'o', or 'u') in a row, followed by 'n'. So it
will match "moon" or "mean" or "moan" or "man", but not "mpg" or "marvelous"
or "men".
You can learn more about regexes here:
http://docs.python.org/library/re.html
http://docs.python.org/howto/regex.html
--
Steven
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Re: [Tutor] user created lists
On 12/04/2012 05:42, john moore wrote: Hello Pyhton World, Hello Hojn Rooem and welcome :) I'm new at this and was wondering how I create a number of user specified lists? Why? Tell us what you're trying to achieve and we may well come up with a better solution. Example: "How many list would you like to create?" User inputs 5 creates five lists, list1 [] list2 [] list3 [] list4 [] list5 [] I can create one with append, but I don't know how to loop it to create five different named list.. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor -- Cheers. Mark Lawrence. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] write list to columns
On 12/04/2012 08:48, Alan Gauld wrote: On 12/04/12 03:31, questions anon wrote: I am trying to simply write a list of values to txt file in one column. I would then like to add another list in a second column. That's going to be quite awkward to do. Files like to be written one complete line at a time. The normal approach would be to build up the table structure in memory and then write the entire table out in one go. If it won't fit in memory use a simple database like SQLite to build the table then print that out row by row. Built-in zip? Or have I missed something? Somehow they only appear as one long row. You need to write newlines but you probably also want to use string formatting to control the amount of space required so that your columns line up. HTH -- Cheers. Mark Lawrence. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Re.findall()
Hi everyone, I am having trouble understanding re.findall(). I've read through the documentation and looked at at some examples online, but I still don't have a clear picture. I am going through pythonchallenge.com and I am on challenge 3. I've see. The answer to the problem, but I don't understand the "pattern" portion of re.findall(). Thanks! Sent from my iPhone ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] should we use multithreading for multiple clients in socket class
I am learning networking and just wrote a primitive client server program..
server:
from time import ctimefrom socket import *
HOST = ""PORT = 21567BUFSIZ = 1024ADDR = (HOST, PORT)
tcpSerSoc = socket(AF_INET, SOCK_STREAM)tcpSerSoc.bind(ADDR)tcpSerSoc.listen(5)
while True:print "waiting for connection.."tcpCliSoc, addr =
tcpSerSoc.accept()print "# Connected from:", addrwhile True:
data = tcpCliSoc.recv(BUFSIZ)if not data:break
tcpCliSoc.send( "[%s] %s" % (ctime(), data ))
tcpCliSoc.clock()tcpSerSoc.close()
Client:
from socket import *
HOST = 'localhost'PORT = 21567BUFSIZ = 1024ADDR = (HOST, PORT)
tcpCliSoc = socket(AF_INET, SOCK_STREAM)tcpCliSoc.connect(ADDR)
while True:data = raw_input(">")if not data:break
tcpCliSoc.send(data)data = tcpCliSoc.recv(BUFSIZ)if not data:
breakprint datatcpCliSoc.close()
This client sends a string, and receives the same string with current time...
So, I tried to run another client (same code but from different file) but found
that its now working.
why its happening, should I use multithreading so that I can handle two clients
simultaneously??
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Re: [Tutor] write list to columns
On 12/04/12 06:33, questions anon wrote:
Perfect, thank you.
Is there a way I could easily/quickly add headings to each column?
Headings are no different to any other line of text...
with open('output.txt', 'w') as f:
write your headings here
for record in records:
f.write(output_format %(record))
f.write('\n')
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
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Re: [Tutor] user created lists
On 12/04/12 08:25, Christian Witts wrote: I recommend that you bite the bullet and use a dedicated dictionary or list to hold your five lists from the very begining: You could use globals() then instead of var(), although it's a do-it-at-your-own-risk situation then if you overwrite built-ins and other functions in the namespace. Creating your own dictionary with the 'variable name' as the key, would be the nicer solution instead. Trying to create variables on the fly is usually a bad idea, although it seems to appeal to beginners a lot. The problem is: how does the rest of the pre-existing code know about these new variable names so as to access them. If you keep the new values in a collection they can be access via a loop. But randomly named variables in your code require all sorts of extra effort to create the name and deference the namespace each time you want to access them. Anonymous values are best kept in anonymous structures IMHO. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] write list to columns
On 12/04/12 03:31, questions anon wrote: I am trying to simply write a list of values to txt file in one column. I would then like to add another list in a second column. That's going to be quite awkward to do. Files like to be written one complete line at a time. The normal approach would be to build up the table structure in memory and then write the entire table out in one go. If it won't fit in memory use a simple database like SQLite to build the table then print that out row by row. Somehow they only appear as one long row. You need to write newlines but you probably also want to use string formatting to control the amount of space required so that your columns line up. HTH -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] user created lists
On 2012/04/12 08:59 AM, Peter Otten wrote: Christian Witts wrote: On 2012/04/12 06:42 AM, john moore wrote: Hello Pyhton World, I'm new at this and was wondering how I create a number of user specified lists? Example: "How many list would you like to create?" User inputs 5 creates five lists, list1 [] list2 [] list3 [] list4 [] list5 [] I can create one with append, but I don't know how to loop it to create five different named list.. You can use vars() to create the variables on the fly. vars() is just a dictionary containing the variable name as the key, and the data as the value so you can do `vars()['list1'] = []` and it's easy enough to create them en masse # Set the start to 1, and add 1 to what the user inputted # as range/xrange doesn't include the top number for i in xrange(1, user_input + 1): vars()['list%s' % i] = [] This will stop working once you move your code into a function: def f(): ... vars()["list1"] = ["a", "b"] ... print list1 ... f() Traceback (most recent call last): File "", line 1, in File "", line 3, in f NameError: global name 'list1' is not defined I recommend that you bite the bullet and use a dedicated dictionary or list to hold your five lists from the very begining: You could use globals() then instead of var(), although it's a do-it-at-your-own-risk situation then if you overwrite built-ins and other functions in the namespace. Creating your own dictionary with the 'variable name' as the key, would be the nicer solution instead. -- Christian Witts Python Developer // ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python connect() function
Pierre Barthelemy wrote:
> I have a question about event handling and the use of the connect
> function. I have a data object, that contains a series of signals, one
> being "new_data_point" .
>
> When i want to plot the data, i also connect the "new_data_point" event to
> the function "analysis_client.update_plot". I therefore run the line:
>
> data.connect('new_data_point', analysis_client.update_plot)
>
> In this case, everytime the data object is updated, i also update the
> plot.
>
>
> I would like to adapt this code to allow to have several plots, connected
> to several data objects. I would therefore need to specify, when i connect
> the "update_plot" function, which plots needs to be updated.
> Is it possible to specify arguments to be used by the connected function
> when the event occurs ? For instance, is there a way to write something
> like:
>
> data.connect('new_data_point',
> analysis_client.update_plot(specific_plot_instance))
>
> So that when the event occurs, the corresponding plot (and only this one)
> is updated ?
Like Walter I have no idea what framework or library you are talking about.
The generic answer is yes: Basically you have to make a new function that
calls the method with a specifc plot instance.
def update_specific_plot():
analysis_client.update_plot(specific_plot_instance)
data.connect("new_data_point", update_specific_plot)
A more elegant and more general version of the above would create the helper
function on the fly using functools.partial():
from functools import partial
data.connect("new_data_point",
partial(analysis_client.update_plot, specific_plot_instance))
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Re: [Tutor] user created lists
Christian Witts wrote:
> On 2012/04/12 06:42 AM, john moore wrote:
>> Hello Pyhton World,
>>
>> I'm new at this and was wondering how I create a number of user specified
>> lists?
>>
>> Example:
>>
>> "How many list would you like to create?"
>> User inputs 5
>> creates five lists,
>> list1 []
>> list2 []
>> list3 []
>> list4 []
>> list5 []
>>
>> I can create one with append, but I don't know how to loop it to create
>> five different named list..
> You can use vars() to create the variables on the fly. vars() is just a
> dictionary containing the variable name as the key, and the data as the
> value so you can do `vars()['list1'] = []` and it's easy enough to
> create them en masse
>
> # Set the start to 1, and add 1 to what the user inputted
> # as range/xrange doesn't include the top number
> for i in xrange(1, user_input + 1):
> vars()['list%s' % i] = []
This will stop working once you move your code into a function:
>>> def f():
... vars()["list1"] = ["a", "b"]
... print list1
...
>>> f()
Traceback (most recent call last):
File "", line 1, in
File "", line 3, in f
NameError: global name 'list1' is not defined
I recommend that you bite the bullet and use a dedicated dictionary or list
to hold your five lists from the very begining:
>>> num_lists = int(raw_input("How many lists? "))
How many lists? 5
>>> list_of_lists = [[] for i in range(num_lists)]
You then have to access the first list as "list_of_list[0]" instead of
"list1" and so on:
>>> list_of_lists[0].append(1)
>>> list_of_lists[4].append(2)
>>> list_of_lists
[[1], [], [], [], [2]]
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