What regex pattern do I need for this?

Question

I need a regex (to work in PHP) to replace American English words in HTML with British English words. So color would be replaced by colour, meters by metres and so on [I kno

Answer 1

The second problem is easier - you want to replace when there are word boundaries around the word: http://www.regular-expressions.info/wordboundaries.html -- this will make sure you don't replace the meter in Brammeter.

The first problem is much harder. You don't want to replace words inside HTML entities - nothing between <> characters. So, your match must make sure that you last saw > or nothing, but never just <. This is either hard, and requires some combination of lookahead/lookbehind assertions, or just plain impossible with regular expressions.

a script implementing a state machine would work much better here.