By using this site, you agree to our updated Privacy Policy and our Terms of Use. Manage your Cookies Settings.
445,909 Members | 2,016 Online
Bytes IT Community
+ Ask a Question
Need help? Post your question and get tips & solutions from a community of 445,909 IT Pros & Developers. It's quick & easy.

Python new user question - file writeline error

P: n/a
Hello,

I'm a newbie to Python & wondering someone can help me with this...

I have this code:
--------------------------
#! /usr/bin/python

import sys

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')

for line in infile:
item = line.split(',')
dob = item[6].split('/')
dob = dob[2]+'-'+str(month[dob[1]])+'-'+dob[0]
lbdt = item[8].split('/')
lbdt = lbdt[2]+'-'+str(month[lbdt[1]])+'-'+lbdt[0]
lbrc = item[10].split('/')
lbrc = lbrc[2]+'-'+str(month[lbrc[1]])+'-'+lbrc[0]
lbrp = item[14].split('/')
lbrp = lbrp[2]+'-'+str(month[lbrp[1]])+'-'+lbrp[0]
item[6] = dob
item[8] = lbdt
item[10]=lbrc
item[14]=lbrp
list = ','.join(item)
outfile.writelines(list)
infile.close
outfile.close
-----------------------------

And the data file(TVA-0316) looks like this:
-----------------------------
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,AST,19,U/L,5,40,,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,GGT,34,U/L,11,32,h,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,ALT,31,U/L,5,29,h,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,ALKP,61,U/L,40,135,,
-----------------------------

Basically I'm reading in each line and converting all date fields (05/
MAR/1950) to different format (1950-03-05) in order to load into MySQL
table.

I have two issues:
1. the outfile doesn't complete with no error message. when I check
the last line in the python interpreter, it has read and processed the
last line, but the output file stopped before.
2. Is this the best way to do this in Python?
3. (Out of scope) is there a way to load this CSV file directly into
MySQL data field without converting the format?

Thank you.

James

Feb 7 '07 #1
Share this Question
Share on Google+
13 Replies


P: n/a
James a écrit :
Hello,

I'm a newbie to Python & wondering someone can help me with this...

I have this code:
--------------------------
#! /usr/bin/python

import sys

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')

for line in infile:
item = line.split(',')
CSV format ?
http://docs.python.org/lib/module-csv.html
dob = item[6].split('/')
dob = dob[2]+'-'+str(month[dob[1]])+'-'+dob[0]
Why did you use integers as values in the month dict if it's for using
them as strings ?
lbdt = item[8].split('/')
lbdt = lbdt[2]+'-'+str(month[lbdt[1]])+'-'+lbdt[0]
lbrc = item[10].split('/')
lbrc = lbrc[2]+'-'+str(month[lbrc[1]])+'-'+lbrc[0]
lbrp = item[14].split('/')
lbrp = lbrp[2]+'-'+str(month[lbrp[1]])+'-'+lbrp[0]
This may help too:
http://docs.python.org/lib/module-datetime.html
item[6] = dob
item[8] = lbdt
item[10]=lbrc
item[14]=lbrp
list = ','.join(item)
Better to avoid using builtin types names as identifiers. And FWIW, this
is *not* a list...
outfile.writelines(list)
You want file.writeline() or file.write(). And you have to manually add
the newline.
infile.close
You're not actually *calling* infile.close - just getting a reference on
the file.close method. The parens are not optional in Python, they are
the call operator.
outfile.close
Idem.
-----------------------------

And the data file(TVA-0316) looks like this:
-----------------------------
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,AST,19,U/L,5,40,,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,GGT,34,U/L,11,32,h,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,ALT,31,U/L,5,29,h,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,ALKP,61,U/L,40,135,,
-----------------------------

Basically I'm reading in each line and converting all date fields (05/
MAR/1950) to different format (1950-03-05) in order to load into MySQL
table.

I have two issues:
1. the outfile doesn't complete with no error message. when I check
the last line in the python interpreter, it has read and processed the
last line, but the output file stopped before.
Use the csv module and cleanly close your files, then come back if you
still have problems.
2. Is this the best way to do this in Python?
Err... What to say... Obviously, no.
Feb 7 '07 #2

P: n/a
On 7 Feb 2007 11:31:32 -0800, James <ci***********@gmail.comwrote:
Hello,

I'm a newbie to Python & wondering someone can help me with this...

I have this code:
--------------------------
#! /usr/bin/python

import sys

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')

for line in infile:
item = line.split(',')
dob = item[6].split('/')
dob = dob[2]+'-'+str(month[dob[1]])+'-'+dob[0]
lbdt = item[8].split('/')
lbdt = lbdt[2]+'-'+str(month[lbdt[1]])+'-'+lbdt[0]
lbrc = item[10].split('/')
lbrc = lbrc[2]+'-'+str(month[lbrc[1]])+'-'+lbrc[0]
lbrp = item[14].split('/')
lbrp = lbrp[2]+'-'+str(month[lbrp[1]])+'-'+lbrp[0]
item[6] = dob
item[8] = lbdt
item[10]=lbrc
item[14]=lbrp
list = ','.join(item)
outfile.writelines(list)
infile.close
outfile.close
-----------------------------

And the data file(TVA-0316) looks like this:
-----------------------------
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,AST,19,U/L,5,40,,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,GGT,34,U/L,11,32,h,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,ALT,31,U/L,5,29,h,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,ALKP,61,U/L,40,135,,
-----------------------------

Basically I'm reading in each line and converting all date fields (05/
MAR/1950) to different format (1950-03-05) in order to load into MySQL
table.

I have two issues:
1. the outfile doesn't complete with no error message. when I check
the last line in the python interpreter, it has read and processed the
last line, but the output file stopped before.
2. Is this the best way to do this in Python?
3. (Out of scope) is there a way to load this CSV file directly into
MySQL data field without converting the format?

Thank you.

James

--
http://mail.python.org/mailman/listinfo/python-list

Your script worked for me. I'm not sure what the next step is in
troubleshooting it. Is it possible that your whitespace isn't quite
right? I had to reformat it, but I assume it was because of the way
cut & paste worked from Gmail.

I usually use Perl for data stuff like this, but I don't see why
Python wouldn't be a great solution. However, I would re-write it
using regexes, to seek and replace sections that are formatted like a
date, rather than breaking it into a variable for each field, changing
each date individually, then putting them back together.

As for how MySQL likes having dates formatted in CSV input: I can't
help there, but I'm sure someone else can.

I'm pretty new to Python myself, but if you'd like help with a
Perl/regex solution, I'm up for it. For that matter, whipping up a
Python/regex solution would probably be good for me. Let me know.

Shawn
Feb 7 '07 #3

P: n/a
On Feb 7, 4:59 pm, "Shawn Milo" <S...@Milochik.comwrote:
On 7 Feb 2007 11:31:32 -0800, James <cityhunter...@gmail.comwrote:
Hello,
I'm a newbie to Python & wondering someone can help me with this...
I have this code:
--------------------------
#! /usr/bin/python
import sys
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')
for line in infile:
item = line.split(',')
dob = item[6].split('/')
dob = dob[2]+'-'+str(month[dob[1]])+'-'+dob[0]
lbdt = item[8].split('/')
lbdt = lbdt[2]+'-'+str(month[lbdt[1]])+'-'+lbdt[0]
lbrc = item[10].split('/')
lbrc = lbrc[2]+'-'+str(month[lbrc[1]])+'-'+lbrc[0]
lbrp = item[14].split('/')
lbrp = lbrp[2]+'-'+str(month[lbrp[1]])+'-'+lbrp[0]
item[6] = dob
item[8] = lbdt
item[10]=lbrc
item[14]=lbrp
list = ','.join(item)
outfile.writelines(list)
infile.close
outfile.close
-----------------------------
And the data file(TVA-0316) looks like this:
-----------------------------
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,AST,19,U/L,5,40,,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,GGT,34,U/L,11,32,h,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,ALT,31,U/L,5,29,h,
06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/
NOV/2006,V1,,,21/NOV/2006,ALKP,61,U/L,40,135,,
-----------------------------
Basically I'm reading in each line and converting all date fields (05/
MAR/1950) to different format (1950-03-05) in order to load into MySQL
table.
I have two issues:
1. the outfile doesn't complete with no error message. when I check
the last line in the python interpreter, it has read and processed the
last line, but the output file stopped before.
2. Is this the best way to do this in Python?
3. (Out of scope) is there a way to load this CSV file directly into
MySQL data field without converting the format?
Thank you.
James
--
http://mail.python.org/mailman/listinfo/python-list

Your script worked for me. I'm not sure what the next step is in
troubleshooting it. Is it possible that your whitespace isn't quite
right? I had to reformat it, but I assume it was because of the way
cut & paste worked from Gmail.

I usually use Perl for data stuff like this, but I don't see why
Python wouldn't be a great solution. However, I would re-write it
using regexes, to seek and replace sections that are formatted like a
date, rather than breaking it into a variable for each field, changing
each date individually, then putting them back together.

As for how MySQL likes having dates formatted in CSV input: I can't
help there, but I'm sure someone else can.

I'm pretty new to Python myself, but if you'd like help with a
Perl/regex solution, I'm up for it. For that matter, whipping up a
Python/regex solution would probably be good for me. Let me know.

Shawn
Thank you very much for your kind offer.
I'm also coming from Perl myself - heard many good things about Python
so I'm trying it out - but it seems harder than I thought :(

James

Feb 7 '07 #4

P: n/a
James a écrit :
On Feb 7, 4:59 pm, "Shawn Milo" <S...@Milochik.comwrote:
(snip)
>>I'm pretty new to Python myself, but if you'd like help with a
Perl/regex solution, I'm up for it. For that matter, whipping up a
Python/regex solution would probably be good for me. Let me know.

Shawn


Thank you very much for your kind offer.
I'm also coming from Perl myself - heard many good things about Python
so I'm trying it out - but it seems harder than I thought :(
If I may comment, Python is not Perl, and trying to solve things the
Perl way, while still possible, may not be the best idea (I don't mean
Perl is a bad idea in itself - just that it's another language with
another way to do things).

Here, doing the parsing oneself - either manually as james did or with
regexps - is certainly not as easy as with Perl, and IMHO not the
simplest way to go, when the csv module can take care of parsing and
formatting CSV files and the datetime module of parsing and formatting
dates.

Just my 2 cents...

Feb 7 '07 #5

P: n/a
On 7 Feb 2007 11:31:32 -0800, James <ci***********@gmail.comwrote:
I have this code:
....
infile.close
outfile.close
....
1. the outfile doesn't complete with no error message. when I check
the last line in the python interpreter, it has read and processed the
last line, but the output file stopped before.
You need to call the close methods on your file objects like this:
outfile.close()

If you leave off the parentheses, you get the method object, but don't
do anything with it.
2. Is this the best way to do this in Python?
I would parse your dates using the python time module, like this:

Python 2.5 (r25:51908, Sep 19 2006, 09:52:17) [MSC v.1310 32 bit
(Intel)] on win32
IDLE 1.2
>>import time
line = r'06-0588,03,701,03701,0000046613,JJB,05/MAR/1950,M,20/NOV/2006,08:50,21/NOV/2006,V1,,,21/NOV/2006,AST,19,U/L,5,40,,'
item = line.split(',')
time.strftime('%a, %d %b %Y', timedate)
'Sun, 05 Mar 1950'
>>dob = item[6]
dob_time = time.strptime(dob, '%d/%b/%Y')
dob_time
(1950, 3, 5, 0, 0, 0, 6, 64, -1)
>>time.strftime('%Y-%m-%d', dob_time)
'1950-03-05'

See the docs for the time module here:
http://docs.python.org/lib/module-time.html
Using that will probably result in code that's quite a bit easier to
read if you ever have to come back to it.

You also might want to investigate the csv module
(http://docs.python.org/lib/module-csv.html) for a bunch of tools
specifically tailored to working with files full of comma separated
values like your input files.

--
Jerry
Feb 7 '07 #6

P: n/a
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
Feb 8 '07 #7

P: n/a
On 8 feb, 12:41, "Shawn Milo" <S...@Milochik.comwrote:
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

Feb 8 '07 #8

P: n/a
On 8 Feb 2007 09:05:51 -0800, Gabriel Genellina <ga******@yahoo.com.arwrote:
On 8 feb, 12:41, "Shawn Milo" <S...@Milochik.comwrote:
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()
Feb 8 '07 #9

P: n/a
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
Feb 8 '07 #10

P: n/a
On 2/8/07, Jussi Salmela <ti*********@hotmail.comwrote:
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
Feb 8 '07 #11

P: n/a
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.
Feb 8 '07 #12

P: n/a
On Feb 8, 3:26 pm, Bruno Desthuilliers
<bdesth.quelquech...@free.quelquepart.frwrote:
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':1 2}
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! :)

Feb 8 '07 #13

P: n/a
En Thu, 08 Feb 2007 14:20:57 -0300, Shawn Milo <Sh***@Milochik.com>
escribió:
On 8 Feb 2007 09:05:51 -0800, Gabriel Genellina <ga******@yahoo.com.ar>
wrote:
>On 8 feb, 12:41, "Shawn Milo" <S...@Milochik.comwrote:
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

Feb 9 '07 #14

This discussion thread is closed

Replies have been disabled for this discussion.