Re: Fwd: Python new user question - file writeline error
En Thu, 08 Feb 2007 14:20:57 -0300, Shawn Milo <[EMAIL PROTECTED]>
escribió:
> On 8 Feb 2007 09:05:51 -0800, Gabriel Genellina <[EMAIL PROTECTED]>
> wrote:
>> On 8 feb, 12:41, "Shawn Milo" <[EMAIL PROTECTED]> wrote:
>>
>> > I have come up with something that's working fine. However, I'm fairly
>> > new to Python, so I'd really appreciate any suggestions on how this
>> > can be made more Pythonic.
>>
>> A few comments:
>>
>> You don't need the formatDatePart function; delete it, and replace
>> newDate = ",%s-%s-%s," % (yearNum,monthNum,dayNum)
>> with
>> newDate = ",%04.4d-%02.2d-%02.2d," % (yearNum,monthNum,dayNum)
>>
>> and before:
>> dayNum, monthNum, yearNum = [int(num) for num in
>> someDate[1:-1].split('/')]
>>
>> And this: outfile.writelines(line)
>> should be: outfile.write(line)
>> (writelines works almost by accident here).
>>
>> You forget again to use () to call the close methods:
>> infile.close()
>> outfile.close()
>>
>> I don't like the final replace, but for a script like this I think
>> it's OK.
>>
>> --
>> Gabriel Genellina
>>
>> --
>> http://mail.python.org/mailman/listinfo/python-list
>>
>
>
> Gabriel,
>
> Thanks for the comments! The new version is below. I thought it made a
> little more sense to format the newDate = ... line the way I have it
> below, although I did incorporate your suggestions.
Looks pretty good for me!
Just one little thing I would change, the variables monthNum, dayNum etc.;
the suffix might indicate that they're numbers, but they're strings
instead. So I would move the int(...) a few lines above, where the
variables are defined.
But that's just a cosmetic thing and just a matter of taste.
> Also, the
> formatting options you provided seemed to specify not only string
> padding, but also decimal places, so I changed it. Please let me know
> if there is some other meaning behind the way you did it.
No, it has no meaning, at least for this range of values.
> As for not liking the replace line, what would you suggest instead?
You already have scanned the line to find the matching fragment; the match
object knows exactly where it begins and ends; so one could replace it
with the reformatted value without searching again, wich takes some more
time, at least in principle.
But this makes the code a bit more complex, and it would only make sense
if you were to process millions of lines, and even then, the execution
might be I/O-bound so you would gain nothing at the end.
That's why I think it's OK as it is now.
--
Gabriel Genellina
--
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Re: Fwd: Python new user question - file writeline error
On Feb 8, 3:26 pm, Bruno Desthuilliers
<[EMAIL PROTECTED]> wrote:
> Shawn Milo a écrit :
>
>
>
> > To the list:
>
> > I have come up with something that's working fine. However, I'm fairly
> > new to Python, so I'd really appreciate any suggestions on how this
> > can be made more Pythonic.
>
> > Thanks,
> > Shawn
>
> > Okay, here's what I have come up with:
>
> > #! /usr/bin/python
>
> > import sys
> > import re
>
> > month
> > ={'JAN':1,'FEB':2,'MAR':3,'APR':4,'MAY':5,'JUN':6,'JUL':7,'AUG':8,'SEP':9,'OCT':10,'NOV':11,'DEC':12}
>
> > infile=file('TVA-0316','r')
> > outfile=file('tmp.out','w')
>
> > def formatDatePart(x):
> >"take a number and transform it into a two-character string,
> > zero padded"
> >x = str(x)
> >while len(x) < 2:
> >x = "0" + x
> >return x
>
> x = "%02d" % x
>
> > regex = re.compile(r",\d{2}/[A-Z]{3}/\d{4},")
>
> regexps are not really pythonic - we tend to use them only when we have
> no better option. When it comes to parsing CSV files and/or dates, we do
> have better solution : the csv module and the datetime module
>
> > for line in infile:
> >matches = regex.findall(line)
> >for someDate in matches:
>
> >dayNum = formatDatePart(someDate[1:3])
> >monthNum = formatDatePart(month[someDate[4:7]])
> >yearNum = formatDatePart(someDate[8:12])
>
> >newDate = ",%s-%s-%s," % (yearNum,monthNum,dayNum)
> >line = line.replace(someDate, newDate)
> >outfile.writelines(line)
>
> > infile.close
> > outfile.close
>
> I wonder why some of us took time to answer your first question. You
> obviously forgot to read these answers.
No offense - but the fact that 're' module is available, doesn't that
mean we can use it? (Pythonic or not - not sure what is really
pythonic at this stage of learning...)
Like Perl, I'm sure there are more than one way to solve problems in
Python.
I appreciate everyone's feedback - I definitely got more than
expected, but it feels comforting that people do care about writing
better codes! :)
--
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Re: Fwd: Python new user question - file writeline error
Shawn Milo a écrit :
> To the list:
>
> I have come up with something that's working fine. However, I'm fairly
> new to Python, so I'd really appreciate any suggestions on how this
> can be made more Pythonic.
>
> Thanks,
> Shawn
>
>
>
>
>
>
> Okay, here's what I have come up with:
>
>
> #! /usr/bin/python
>
> import sys
> import re
>
> month
> ={'JAN':1,'FEB':2,'MAR':3,'APR':4,'MAY':5,'JUN':6,'JUL':7,'AUG':8,'SEP':9,'OCT':10,'NOV':11,'DEC':12}
>
>
> infile=file('TVA-0316','r')
> outfile=file('tmp.out','w')
>
> def formatDatePart(x):
>"take a number and transform it into a two-character string,
> zero padded"
>x = str(x)
>while len(x) < 2:
>x = "0" + x
>return x
x = "%02d" % x
> regex = re.compile(r",\d{2}/[A-Z]{3}/\d{4},")
regexps are not really pythonic - we tend to use them only when we have
no better option. When it comes to parsing CSV files and/or dates, we do
have better solution : the csv module and the datetime module
> for line in infile:
>matches = regex.findall(line)
>for someDate in matches:
>
>dayNum = formatDatePart(someDate[1:3])
>monthNum = formatDatePart(month[someDate[4:7]])
>yearNum = formatDatePart(someDate[8:12])
>
>newDate = ",%s-%s-%s," % (yearNum,monthNum,dayNum)
>line = line.replace(someDate, newDate)
>outfile.writelines(line)
>
> infile.close
> outfile.close
I wonder why some of us took time to answer your first question. You
obviously forgot to read these answers.
--
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Re: Fwd: Python new user question - file writeline error
On 2/8/07, Jussi Salmela <[EMAIL PROTECTED]> wrote:
> Shawn Milo kirjoitti:
> > To the list:
> >
> > I have come up with something that's working fine. However, I'm fairly
> > new to Python, so I'd really appreciate any suggestions on how this
> > can be made more Pythonic.
> >
> > Thanks,
> > Shawn
> >
> >
> >
> >
> >
> >
> > Okay, here's what I have come up with:
>
> What follows may feel harsh but you asked for it ;)
>
> >
> >
> > #! /usr/bin/python
> >
> > import sys
> > import re
> >
> > month
> > ={'JAN':1,'FEB':2,'MAR':3,'APR':4,'MAY':5,'JUN':6,'JUL':7,'AUG':8,'SEP':9,'OCT':10,'NOV':11,'DEC':12}
> >
> > infile=file('TVA-0316','r')
> > outfile=file('tmp.out','w')
> >
> > def formatDatePart(x):
> >"take a number and transform it into a two-character string,
> > zero padded"
> If a comment or doc string is misleading one would be better off without
> it entirely:
> "take a number": the function can in fact take (at least)
> any base type
> "transform it": the function doesn't transform x to anything
> although the name of the variable x is the same
> as the argument x
> "two-character string": to a string of at least 2 chars
> "zero padded": where left/right???
> >x = str(x)
> >while len(x) < 2:
> >x = "0" + x
> You don't need loops for these kind of things. One possibility is to
> replace the whole body with:
> return str(x).zfill(2)
> >return x
> >
> > regex = re.compile(r",\d{2}/[A-Z]{3}/\d{4},")
> >
> > for line in infile:
> >matches = regex.findall(line)
> >for someDate in matches:
> >
> Empty lines are supposed to make code more readable. The above empty
> line does the contrary by separating the block controlled by the for
> and the for statement
> >dayNum = formatDatePart(someDate[1:3])
> >monthNum = formatDatePart(month[someDate[4:7]])
> >yearNum = formatDatePart(someDate[8:12])
> You don't need the formatDatePart function at all:
> newDate = ",%4s-%02d-%2s," % \
> (someDate[8:12],month[someDate[4:7]],someDate[1:3])
> >
> >newDate = ",%s-%s-%s," % (yearNum,monthNum,dayNum)
> >line = line.replace(someDate, newDate)
> >
> >outfile.writelines(line)
> >
> > infile.close
> > outfile.close
> You have not read the answers given to the OP, have you. Because if you
> had, your code would be:
> infile.close()
> outfile.close()
> The reason your version seems to be working, is that you probably
> execute your code from the command-line and exiting from Python to
> command-line closes the files, even if you don't.
>
> Cheers,
> Jussi
> --
> http://mail.python.org/mailman/listinfo/python-list
>
Jussi,
Thanks for the feedback. I received similar comments on a couple of
those items, and posted a newer version an hour or two ago. I think
the only thing missing there is a friendly blank line after my "for
line in infile:" statement.
Please let me know if there is anything else.
Shawn
--
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Re: Fwd: Python new user question - file writeline error
Shawn Milo kirjoitti:
> To the list:
>
> I have come up with something that's working fine. However, I'm fairly
> new to Python, so I'd really appreciate any suggestions on how this
> can be made more Pythonic.
>
> Thanks,
> Shawn
>
>
>
>
>
>
> Okay, here's what I have come up with:
What follows may feel harsh but you asked for it ;)
>
>
> #! /usr/bin/python
>
> import sys
> import re
>
> month
> ={'JAN':1,'FEB':2,'MAR':3,'APR':4,'MAY':5,'JUN':6,'JUL':7,'AUG':8,'SEP':9,'OCT':10,'NOV':11,'DEC':12}
>
>
> infile=file('TVA-0316','r')
> outfile=file('tmp.out','w')
>
> def formatDatePart(x):
>"take a number and transform it into a two-character string,
> zero padded"
If a comment or doc string is misleading one would be better off without
it entirely:
"take a number": the function can in fact take (at least)
any base type
"transform it": the function doesn't transform x to anything
although the name of the variable x is the same
as the argument x
"two-character string": to a string of at least 2 chars
"zero padded": where left/right???
>x = str(x)
>while len(x) < 2:
>x = "0" + x
You don't need loops for these kind of things. One possibility is to
replace the whole body with:
return str(x).zfill(2)
>return x
>
> regex = re.compile(r",\d{2}/[A-Z]{3}/\d{4},")
>
> for line in infile:
>matches = regex.findall(line)
>for someDate in matches:
>
Empty lines are supposed to make code more readable. The above empty
line does the contrary by separating the block controlled by the for
and the for statement
>dayNum = formatDatePart(someDate[1:3])
>monthNum = formatDatePart(month[someDate[4:7]])
>yearNum = formatDatePart(someDate[8:12])
You don't need the formatDatePart function at all:
newDate = ",%4s-%02d-%2s," % \
(someDate[8:12],month[someDate[4:7]],someDate[1:3])
>
>newDate = ",%s-%s-%s," % (yearNum,monthNum,dayNum)
>line = line.replace(someDate, newDate)
>
>outfile.writelines(line)
>
> infile.close
> outfile.close
You have not read the answers given to the OP, have you. Because if you
had, your code would be:
infile.close()
outfile.close()
The reason your version seems to be working, is that you probably
execute your code from the command-line and exiting from Python to
command-line closes the files, even if you don't.
Cheers,
Jussi
--
http://mail.python.org/mailman/listinfo/python-list
Re: Fwd: Python new user question - file writeline error
On 8 Feb 2007 09:05:51 -0800, Gabriel Genellina <[EMAIL PROTECTED]> wrote:
> On 8 feb, 12:41, "Shawn Milo" <[EMAIL PROTECTED]> wrote:
>
> > I have come up with something that's working fine. However, I'm fairly
> > new to Python, so I'd really appreciate any suggestions on how this
> > can be made more Pythonic.
>
> A few comments:
>
> You don't need the formatDatePart function; delete it, and replace
> newDate = ",%s-%s-%s," % (yearNum,monthNum,dayNum)
> with
> newDate = ",%04.4d-%02.2d-%02.2d," % (yearNum,monthNum,dayNum)
>
> and before:
> dayNum, monthNum, yearNum = [int(num) for num in
> someDate[1:-1].split('/')]
>
> And this: outfile.writelines(line)
> should be: outfile.write(line)
> (writelines works almost by accident here).
>
> You forget again to use () to call the close methods:
> infile.close()
> outfile.close()
>
> I don't like the final replace, but for a script like this I think
> it's OK.
>
> --
> Gabriel Genellina
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
Gabriel,
Thanks for the comments! The new version is below. I thought it made a
little more sense to format the newDate = ... line the way I have it
below, although I did incorporate your suggestions. Also, the
formatting options you provided seemed to specify not only string
padding, but also decimal places, so I changed it. Please let me know
if there is some other meaning behind the way you did it.
As for not liking the replace line, what would you suggest instead?
Shawn
#! /usr/bin/python
import sys
import re
month
={'JAN':1,'FEB':2,'MAR':3,'APR':4,'MAY':5,'JUN':6,'JUL':7,'AUG':8,'SEP':9,'OCT':10,'NOV':11,'DEC':12}
infile=file('TVA-0316','r')
outfile=file('tmp.out','w')
regex = re.compile(r",\d{2}/[A-Z]{3}/\d{4},")
for line in infile:
matches = regex.findall(line)
for someDate in matches:
dayNum = someDate[1:3]
monthNum = month[someDate[4:7]]
yearNum = someDate[8:12]
newDate = ",%04d-%02d-%02d," %
(int(yearNum),int(monthNum),int(dayNum))
line = line.replace(someDate, newDate)
outfile.write(line)
infile.close()
outfile.close()
--
http://mail.python.org/mailman/listinfo/python-list
Re: Fwd: Python new user question - file writeline error
On 8 feb, 12:41, "Shawn Milo" <[EMAIL PROTECTED]> wrote:
> I have come up with something that's working fine. However, I'm fairly
> new to Python, so I'd really appreciate any suggestions on how this
> can be made more Pythonic.
A few comments:
You don't need the formatDatePart function; delete it, and replace
newDate = ",%s-%s-%s," % (yearNum,monthNum,dayNum)
with
newDate = ",%04.4d-%02.2d-%02.2d," % (yearNum,monthNum,dayNum)
and before:
dayNum, monthNum, yearNum = [int(num) for num in
someDate[1:-1].split('/')]
And this: outfile.writelines(line)
should be: outfile.write(line)
(writelines works almost by accident here).
You forget again to use () to call the close methods:
infile.close()
outfile.close()
I don't like the final replace, but for a script like this I think
it's OK.
--
Gabriel Genellina
--
http://mail.python.org/mailman/listinfo/python-list
Fwd: Python new user question - file writeline error
To the list:
I have come up with something that's working fine. However, I'm fairly
new to Python, so I'd really appreciate any suggestions on how this
can be made more Pythonic.
Thanks,
Shawn
Okay, here's what I have come up with:
#! /usr/bin/python
import sys
import re
month
={'JAN':1,'FEB':2,'MAR':3,'APR':4,'MAY':5,'JUN':6,'JUL':7,'AUG':8,'SEP':9,'OCT':10,'NOV':11,'DEC':12}
infile=file('TVA-0316','r')
outfile=file('tmp.out','w')
def formatDatePart(x):
"take a number and transform it into a two-character string,
zero padded"
x = str(x)
while len(x) < 2:
x = "0" + x
return x
regex = re.compile(r",\d{2}/[A-Z]{3}/\d{4},")
for line in infile:
matches = regex.findall(line)
for someDate in matches:
dayNum = formatDatePart(someDate[1:3])
monthNum = formatDatePart(month[someDate[4:7]])
yearNum = formatDatePart(someDate[8:12])
newDate = ",%s-%s-%s," % (yearNum,monthNum,dayNum)
line = line.replace(someDate, newDate)
outfile.writelines(line)
infile.close
outfile.close
--
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