Python difflib to compare two csv files and highlight the world level differences in HTML output

Question

I am not an expertise in Python and I tried searching my best to find the answer, but couldn't find. Pardon me, If this is a duplicate question and point me in the right direction, if you can.

I am trying to compare two CSV files using Python Difflib and generating the Diff output as a HTML page. The current difflib module has the inbuilt options as -m to generate the HTML output of the two csv files side by side by highlighting the differences.

However, the difflib uses difflib.SequenceMatcher to find the differences and create a HTML file using difflib.HtmlDiff.make_file . But, the output for that it produces is not that I want.

The output I am getting currently from the difflib is :The Default Python DIFFLIB HTML output is Here.

However, The output I want is : I am looking for a word level highlight instead of the changes that are highlighted either at character level or a sequence highlight. I am looking to highlight the WHOLE WORD if any changed that happened between old file and new file.

The changes that I want to highlight is: A word Level highlight of the text.

Please help me in this regard, whether this is really possible with difflib or do I have to use any other tools/modules. I tried using vimdiff and other plugins, but I am left with nothing. I am open to any thing here.

The code I am using is from PythonDiffLib docs page.

import sys, os, time, difflib, optparse
  def main():
   ..
   ..
   ..
    n = options.lines //I used this n = ZERO.
    fromfile, tofile = args # as specified in the usage string

    # we're passing these as arguments to the diff function
    fromdate = time.ctime(os.stat(fromfile).st_mtime)
    todate = time.ctime(os.stat(tofile).st_mtime)
    fromlines = open(fromfile, 'U').readlines()
    tolines = open(tofile, 'U').readlines()

    diff = difflib.HtmlDiff().make_file(fromlines, tolines, fromfile,
                                            tofile, context=TRUE,
                                            numlines=0)

    # we're using writelines because diff is a generator
    sys.stdout.writelines(diff)

` Old.csv

refno,title,author,year,price
1001,CPP,MILTON,2008,456
1002,JAVA,Gilson,2002,456
1003,Adobe Flex,2010,566
1004,General Knowledge,Sinson,2007,465
1005,Actionscript,Gilto,2008,480

new.csv

refno,title,author,year,price
1001,CPP,MILTON,2010,456,2008
1002,JAVA,Gilson,2002
1003,Adobe Flexi,Johnson,2010,566
1004,General Knowledge,Simpson,2007,465
105,Action script,Gilto,2008,480
2000,Drama,DayoNe,,2020,560

I am also adding the Default HTML DIFF Output and Expected HTML DIFF output below.

Default HTML DIFF Output from DIFFLIB:












  
  

old.csv 
new.csv

t 2 1001,CPP,MILTON,2008,456 t 2 1001,CPP,MILTON,2010,456,2008
3 1002,JAVA,Gilson,2002,456 3 1002,JAVA,Gilson,2002
4 1003,Adobe Flex,2010,566 4 1003,Adobe Flexi,Johnson,2010,566
5 1004,General Knowledge,Sinson,2007,465 5 1004,General Knowledge,Simpson,2007,465
6 1005,Actionscript,Gilto,2008,480 6 105,Action script,Gilto,2008,480
7 2000,Drama,DayoNe,,2020,560

Expected HTML DIFF Output from DIFFLIB:












  
  

old.csv 
new.csv

t 2 1001,CPP,MILTON,2008,456 t 2 1001,CPP,MILTON,2010,456,2008
3 1002,JAVA,Gilson,2002,456 3 1002,JAVA,Gilson,2002
4 1003,Adobe Flex,2010,566 4 1003,Adobe Flexi,Johnson,2010,566
5 1004,General Knowledge,Sinson,2007,465 5 1004,General Knowledge,Simpson,2007,465
6 1005,Actionscript,Gilto,2008,480 6 105,Action script,Gilto,2008,480
7 2000,Drama,DayoNe,,2020,560

stovfl · Accepted Answer

Question: I am looking for a word level highlight

Implements class Comma_HtmlDiff, expand Highlight to Comma boundaries:
You have to Overload difflib.ndiff.

Note: Only expand the first highlighted Part is implemented.
If difflib.ndiff highlights across Comma, this is not corrected.

class Comma_HtmlDiff(difflib.HtmlDiff):
    def __init__(self, tabsize=8, wrapcolumn=None, linejunk=None,
             charjunk=difflib.IS_CHARACTER_JUNK):
        setattr(difflib, '_ndiff', difflib.ndiff)
        setattr(difflib, 'ndiff', self.ndiff)
        super().__init__(tabsize, wrapcolumn, linejunk, charjunk)

    def ndiff(self, a, b, linejunk=None, charjunk=difflib.IS_CHARACTER_JUNK):
        _line = ''
        for line in difflib._ndiff(a, b, linejunk, charjunk):
            if line.startswith('-'):
                _d = '-'
                _line = line
            elif line.startswith('+'):
                _d = '+'
                _line = line

            if line.startswith('?'):
                dp = line.find(_d)
                if dp == -1:
                    _d = '+'
                    dp = line.find('^')
                dpl = _line.rfind(',', 0, dp)
                if dpl == -1:
                    dpl = 2
                else:
                    dpl += 1
                dpr = _line.find(',', dp)
                if dpr == dp:
                    _d = ' '
                    dpl = dp
                    dpr = dp+1

                dpw = dpr - dpl
                line = line[:dpl] + _d*dpw + line[dpr:]

            yield line

# Usage
diff = Comma_HtmlDiff().make_file(fromlines, tolines, fromfile,
                                    tofile, context=True,
                                    numlines=0)

Output:

Tested with Python: 3.4.2

Python difflib to compare two csv files and highlight the world level differences in HTML output

Answers (1)

Related Questions