You know you need at least one digit. So you can use lookahead, to test for it: 
/^([+-]?(?=\d|\.\d)\d*\.?\d*)([a-z]+)$/

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Or you can make a regex out of alternatives: 
/^([+-]?(?:\d+\.?\d*|\.\d+))([a-z]+)$/

[download]

In reply to Re: Identifying and parsing numbers by bart
in thread Identifying and parsing numbers by dragonchild

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