Comments on: A simple diff algorithm in PHP

By: Aviram

Aviram — Tue, 11 Oct 2011 15:29:42 +0000

Great job Paul! you really made my life easier.
One question, I’ve been trying to change your code in a way that if someone changes the location of some text in the new version (cuts and pasts) it will not count as a change. but I’m having trouble to understand who this can be done using your current implementation of diff.

could you please help me?

Thanks!

By: Christian

Christian — Fri, 07 Oct 2011 11:13:02 +0000

Nice code, thanks for this part, especially the htmlDiff is nice!

@Jeff: You need to split the text using another algorithm than explode(), f.e. preg_split(), but it’s not that simple to implode those words again, because you need the “word-split” character again. Maybe you could use a word iterator, but this would produce a huge amount of additional code.

Cheers from Germany,
Chris

By: matt

matt — Tue, 13 Sep 2011 09:13:49 +0000

Hi Paul.

First, I would like to thank you for publishing this. I have not been able to make this work and your solution is very helpful to me.

However, I am having performance issues with this on very large strings, and I cannot figure out how to address them. In the code comments, you said that there are ways to address these issues, and I was wondering, would you would mind sharing them?

By: yarco

yarco — Tue, 23 Aug 2011 01:09:11 +0000

oh, my version is line diff

By: yarco

yarco — Tue, 23 Aug 2011 01:00:33 +0000

I cant use it…dont why, continue saying $maxlen doest define. So i make one by myself,
here it is:
http://bbish.net/05toolsproducts/66/php-simple-diff
I dont even know it is ok or not, but seems good.

By: Jeff

Jeff — Sat, 11 Jun 2011 05:30:52 +0000

I’ve been trying to modify this to include differences in punctuation:

Currently a diff between “I think, therefore” and “I think therefore” will produce:

I ~~think,~~think therefore

I would like it to produce:

I think, therefore

Any thoughts on how to achieve this? I messed around with code referenced by Peter West above but couldn’t get this to work.

By: String diff on punctuation: is preg_split the answer? | Coding Answers

String diff on punctuation: is preg_split the answer? | Coding Answers — Fri, 10 Jun 2011 09:53:04 +0000

[...] http://piratepad.net/IY48xXzsys (modified by Peter West, from the original here: http://paulbutler.org/archives/a-simple-diff-algorithm-in-php/) [...]

By: Mario

Mario — Mon, 16 May 2011 09:59:52 +0000

Works great and saved me a lot of time. Thanks!

By: Andrea

Andrea — Mon, 25 Apr 2011 12:27:25 +0000

Man thanks your function is pretty good.

But why you don’t add those fix ($ret=” and few others) to kill the notices?

Thanks al ot

By: bob

bob — Wed, 23 Mar 2011 01:01:48 +0000

Actually I figured out the problem is that an example like “end\n\nfirst” is treated as one “word”. I first need to “wrap” the decline characters in spaces.

So “end \n \n first”. Then after the check just remove the spaces.