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Answer 1

A:

I modified the following to simply iterate over every combination of lines from file1 and file2. I think the for, else construction works well here.

def comparefiles(file1, file2):
    for row in file1:
        for row in file2:
             #check all of your lines, break if condition is met
        else:
             #no matches

mvrak 2010-10-28 01:51:48

I know this is just a rough guideline but you may also want to check if *file2* contains additional rows that are not in *file1*.

Alexandre Jasmin 2010-10-28 01:54:19

This would certainly work, but is there a way to gather up statistic on "correctness" and not totally die if file2 is missing a record at the beginning? (also keeping in mind i'd be looping through 20+ "file2"s)

nonot1 2010-10-28 02:04:31

The break doesn't totally die, it would only exit the the second for loop. Basically, when you find the match to the line in file 1, the break would say ok I found my match, I no longer have to check file2.

mvrak 2010-10-28 17:16:08

You would invoke this function for each file2 that you are iterating through. What you return from this function is dependent on your use, which you didn't detail here.

mvrak 2010-10-28 17:16:48

Answer 2

A:

I completely agree with unutbu, you should use difflib for that.

difflib.SequenceMatcher(None, file1.read(), file2.read())

pyfunc 2010-10-28 02:17:39

Looking at difflib docs, but it seems built for text. In my case i have non-"string" text data too. 1.9 is "close enough" to 2.0, for instance.

nonot1 2010-10-28 02:28:51

@user489549: you could always do a second pass to sanitize the diff lines. This way, bulk of logic to copare lines will be left to difflib and custom logic can be applied to changed lines. This way the sequencer can also match when multiple lines has been inserted lines appropriately

pyfunc 2010-10-28 02:32:51

@user489549: In fact, it won't die if some lines were missing. It will show up in the diff.

pyfunc 2010-10-28 02:34:23

Can difflib work on custom objects?

nonot1 2010-10-28 02:46:31

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