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nikolay marinov 08-09-2007 01:21 PM

tests
 
Hi, everyone.Does anybody have an idea how can i test two xls files for
equality with Python

kyosohma@gmail.com 08-09-2007 01:41 PM

Re: tests
 
On Aug 9, 8:21 am, nikolay marinov <n.mari...@sistechnology.com>
wrote:
> Hi, everyone.Does anybody have an idea how can i test two xls files for
> equality with Python


You should be able to read chunks of each file in binary mode and do a
compare to check for equality. Some kind of loop should do the trick.

Mike


brad 08-09-2007 02:04 PM

Re: tests
 
kyosohma@gmail.com wrote:

> You should be able to read chunks of each file in binary mode and do a
> compare to check for equality. Some kind of loop should do the trick.


Why not a simple md5 or sha with the hash library?

dijkstra.arjen@gmail.com 08-09-2007 02:43 PM

Re: tests
 
On Aug 9, 4:04 pm, brad <byte8b...@gmail.com> wrote:
> kyoso...@gmail.com wrote:
> > You should be able to read chunks of each file in binary mode and do a
> > compare to check for equality. Some kind of loop should do the trick.

>
> Why not a simple md5 or sha with the hash library?


Or even:

http://docs.python.org/lib/module-filecmp.html


special_dragonfly 08-09-2007 02:46 PM

Re: tests
 

<dijkstra.arjen@gmail.com> wrote in message
news:1186670584.148181.180040@r34g2000hsd.googlegr oups.com...
> On Aug 9, 4:04 pm, brad <byte8b...@gmail.com> wrote:
>> kyoso...@gmail.com wrote:
>> > You should be able to read chunks of each file in binary mode and do a
>> > compare to check for equality. Some kind of loop should do the trick.

>>
>> Why not a simple md5 or sha with the hash library?

>
> Or even:
>
> http://docs.python.org/lib/module-filecmp.html
>


My understanding of reading that is that it only looks at the file names
themselves and not their contents. So whether filename1=filename2 and in the
case of the function below it, whether one directory has files which are in
the other.
Correct me if I'm wrong.
Dom

P.S. md5 or sha hash is what I'd go for, short of doing:

MyFirstFile=file("file1.xls")
MySecondFile=file("file2.xls")
If MyFirstFile==MySecondFile:
print "True"

although this won't tell you where they're different, just that they are...



Jason 08-09-2007 03:01 PM

Re: tests
 
On Aug 9, 8:46 am, "special_dragonfly" <Domi...@PLEASEASK.co.uk>
wrote:
> <dijkstra.ar...@gmail.com> wrote in message
> >http://docs.python.org/lib/module-filecmp.html

>
> My understanding of reading that is that it only looks at the file names
> themselves and not their contents. So whether filename1=filename2 and in the
> case of the function below it, whether one directory has files which are in
> the other.
> Correct me if I'm wrong.
> Dom
>
> P.S. md5 or sha hash is what I'd go for, short of doing:
>
> MyFirstFile=file("file1.xls")
> MySecondFile=file("file2.xls")
> If MyFirstFile==MySecondFile:
> print "True"
>
> although this won't tell you where they're different, just that they are...


You're incorrect. If the shallow flag is not given or is true, the
results of os.stat are used to compare the two files, so if they have
the same size, change times, etc, they're considered the same.

If the shallow flag is given and is false, their contents are
compared. In either case, the results are cached for efficiency's
sake.

--Jason


The documentation for filecmp.cmp is:
cmp( f1, f2[, shallow])
Compare the files named f1 and f2, returning True if they seem
equal, False otherwise.

Unless shallow is given and is false, files with identical
os.stat() signatures are taken to be equal.

Files that were compared using this function will not be
compared again unless their os.stat() signature changes.

Note that no external programs are called from this function,
giving it portability and efficiency.


Steve Holden 08-09-2007 03:55 PM

Re: tests
 
Jason wrote:
> On Aug 9, 8:46 am, "special_dragonfly" <Domi...@PLEASEASK.co.uk>
> wrote:
>> <dijkstra.ar...@gmail.com> wrote in message
>>> http://docs.python.org/lib/module-filecmp.html

>> My understanding of reading that is that it only looks at the file names
>> themselves and not their contents. So whether filename1=filename2 and in the
>> case of the function below it, whether one directory has files which are in
>> the other.
>> Correct me if I'm wrong.
>> Dom
>>
>> P.S. md5 or sha hash is what I'd go for, short of doing:
>>
>> MyFirstFile=file("file1.xls")
>> MySecondFile=file("file2.xls")
>> If MyFirstFile==MySecondFile:
>> print "True"
>>
>> although this won't tell you where they're different, just that they are...

>
> You're incorrect. If the shallow flag is not given or is true, the
> results of os.stat are used to compare the two files, so if they have
> the same size, change times, etc, they're considered the same.
>
> If the shallow flag is given and is false, their contents are
> compared. In either case, the results are cached for efficiency's
> sake.
>
> --Jason
>
>
> The documentation for filecmp.cmp is:
> cmp( f1, f2[, shallow])
> Compare the files named f1 and f2, returning True if they seem
> equal, False otherwise.
>
> Unless shallow is given and is false, files with identical
> os.stat() signatures are taken to be equal.
>
> Files that were compared using this function will not be
> compared again unless their os.stat() signature changes.
>
> Note that no external programs are called from this function,
> giving it portability and efficiency.
>


This discussion seems to assume that Excel spreadsheets are stored in
some canonical form so that two spreads with the same functionality are
always identical on disk to the last bit. I very much doubt this is true
(consider as an example the file properties that can be set).

So really you need to define "equality". So far the tests discussed have
concentrated on identifying identical files.

regards
Steve
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Jay Loden 08-09-2007 04:20 PM

Re: tests
 
Steve Holden wrote:
> This discussion seems to assume that Excel spreadsheets are stored in
> some canonical form so that two spreads with the same functionality are
> always identical on disk to the last bit. I very much doubt this is true
> (consider as an example the file properties that can be set).
>
> So really you need to define "equality". So far the tests discussed have
> concentrated on identifying identical files.
>
> regards
> Steve


I was wondering myself if the OP was actually interested in binary identical
files, or just duplicated content. If just duplicated content, perhaps this
could be used as a starting point:

http://aspn.activestate.com/ASPN/Coo.../Recipe/440661

and the actual data can be compared

-Jay


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