Question

For example, in this text:

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nunc eu tellus vel nunc pretium lacinia. Proin sed lorem. Cras sed ipsum. Nunc a libero quis risus sollicitudin imperdiet.

I want to match the word after ‘ipsum’.

Answer 1

This sounds like a job for lookbehinds, though you should be aware that not all regex flavors support them. In your example:

(?<=\bipsum\s)(\w+) 

This will match any sequence of letter characters which follows ‘ipsum’ as a whole word followed by a space. It does not match ‘ipsum’ itself, you don’t need to worry about reinserting it in the case of, e.g. replacements.

As I said, though, some flavors (JavaScript, for example) don’t support lookbehind at all. Many others (most, in fact) only support ‘fixed width’ lookbehinds — so you could use this example but not any of the repetition operators. (In other words, (?<=\b\w+\s+)(\w+) wouldn’t work.)