How to compare text

Question

Like the title, How to compare text?. For a example, go to textdiff.com.

Answer 1

Check out Levenshtein distance. This is a fairly general algorithm for identifying differences between two strings.

Answer 2

You may want to have a look at Pear's Text_Diff

http://pear.php.net/package/Text_Diff/

Answer 3

http://en.wikipedia.org/wiki/Longest_common_subsequence_problem

Answer 4

if you're looking for a terminal command, check out diff, found in linux by default. You can also have it on windows by installing cygwin [with a LOT of excess baggage. :\ ]

Answer 5

I would suggest Jaccard's Similarity coefficient. Treating each sentence as a unit.