Regex matching numbers and decimals

Question

I need a regex expression that will match the following:

.5
0.5
1.5
1234

but NOT

0.5.5
absnd (any letter character or space         


        

Answer 1

Nobody seems to be accounting for negative numbers. Also, some are creating a capture group which is unnecessary. This is the most thorough solution IMO.

^[+-]?(?:\d*\.)?\d+$