Regular expression to find last word in sentence

Question

How can I find last word in a sentence with a regular expression?

Answer 1

In general you can't correctly parse English text with regular expressions.

The best you can do is to look for some punctuation that usually terminates a sentence but unfortunately this is not a guarantee. For example the text Mr. Bloggs is here. Do you want to talk to him? contains two periods which have different meanings. There is no way for a regular expression to distinguish between the two uses of the period.

I'd suggest instead that you look at a natural language parsing library. For example the Stanford Parser has no trouble at all correctly parsing the above text into the two sentences:

Mr./NNP Bloggs/NNP is/VBZ here/RB ./.
Do/VBP you/PRP want/VB to/TO talk/VB to/TO him/PRP ?/.

There are lots of other freely available NLP libraries that you could use too, I'm not endorsing that one product in particular - it's just an example to demonstrate that it is possible to parse text into sentences with a fairly high reliability. Note though that even a natural language parsing library will still occasionally make a mistake - parsing human languages correctly is hard.