vox wrote: > On Jul 10, 4:17 pm, Dave Angel <da...@ieee.org> wrote: >> vox wrote: >> > On Jul 10, 2:04 pm, Peter Otten <__pete...@web.de> wrote: >> >> >> You are probably misinterpreting len(s3). s3 contains lines occuring >> >> in "file1" but not in "file2". Duplicate lines are only counted once, >> >> and the order doesn't matter. >> >> >> So there are 119 lines that occur at least once in "file2", but not in >> >> "file1". >> >> >> If that is not what you want you have to tell us what exactly you are >> >> looking for. >> >> >> Peter >> >> > Hi, >> > Thanks for the answer. >> >> > I am looking for a script that compares file1 and file2, for each line >> > in file1, check if line is present in file2. If the line from file1 is >> > not present in file2, print that line/write it to file3, because I >> > have to know what lines to add to file2. >> >> > BR, >> > Andy >> >> There's no more detail in that response. To the level of detail you >> provide, the program works perfectly. Just loop through the set and >> write the members to the file. >> >> But you have some unspecified assumptions: >> 1) order doesn't matter >> 2) duplicates are impossible in the input file, or at least not >> meaningful. So the correct output file could very well be smaller than >> either of the input files. >> >> And a few others that might matter: >> 3) the two files are both text files, with identical line endings >> matching your OS default >> 4) the two files are ASCII, or at least 8 bit encoded, using the >> same encoding (such as both UTF-8) >> 5) the last line of each file DOES have a trailing newline sequence > > Thanks all for the input! > I have guess I have to think it through a couple times more. :)
Indeed. Note that others thinking through related problems have come up with http://docs.python.org/library/difflib.html Peter -- http://mail.python.org/mailman/listinfo/python-list