peterscott/diff_match_patch-python

Python extension module for google-diff-match-patch's C++ implementation

diff_match_patch extension module for Python based on google-diff-match-patch ---

google-diff-match-patch is a Google library for computing differences between text files:

http://code.google.com/p/google-diff-match-patch

This project builds an extension module for Python using google-diff-match-patch's C++ implementation. Although google-diff-match-patch has a pure Python implementation, I have a need for speed.

Build Prerequisites:

Python development headers

Debian package: python-dev

Qt 4 development libraries (data structures used by google-diff-match-patch)

Debian package: libqt4-dev

Runtime Prerequisitves:

Qt 4 Core

Debian package: libqtcore4

Build:

python setup.py install

Or you may find pre-built binaries stored in the git repository in the build directory. Your mileage may vary with these depending on whether your system is compatible.

Usage:

import diff_match_patch

left_text = "this is a test" right_text = "this is not a test"

diff = diff_match_patch.diff(left_text, right_text)

for op, length in diff:

if op == "-":

print "next", length, "characters are deleted"

if op == "=":

print "next", length, "characters are in common"

if op == "+":

print "next", length, "characters are inserted"

Options:

diff(left, right) takes an optional argument called timelimit which specifies an upper bound on the amount of time to compute the diff, in seconds, or give zero (the default) to work on the diff indefinitely.

According to the Google docs, the diff will stop working after the time is exceeded and will return a valid diff, but it might not be the best one.