regular expression: efficiency

Hi there,

I haven’t much experience with regular expressions.
I wanted to re-format strings, for example in replacing “_underlined text_” with “<u>underlined text</u>”

I draw up the following rules:

[QUOTE]

1) the “_“-character (open tag) must be after a whitespace or a newline
and before an alphanumeric-character
2) this can be followed by any characters (exept line-breaks)
3) the “_“-character (close tag) must be after an alphanumeric character
and before a whitespace or an endline

[/QUOTE]

and I got the following regexp:

[CODE]#( |^)_([a-z0-9]+)([^<>n]*?)([a-z0-9]+)_( |$)#im[/CODE]

But I think there are more efficient and nicer ways (perhaps there are simpler ways? (what means that they are faster))

thanks ?

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