I think, this would be equivalent:
/^-?(\d*)\.?(\d*)$/
OTOH: I wouldn't consider "-." a legal number.

So maybe this is better?
/^-?((\d+\.\d*)|(\.?\d+))$/
This wouldn't capture like yours does, but the captured parts aren't used. So you might want to consider using (?:...)...

s$$([},&%#}/&/]+}%&{})*;#$&&s&&$^X.($'^"%]=\&(|?*{%
+.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e

In reply to Re^2: combined into a single regex by Skeeve
in thread combined into a single regex by arcnon

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