My regex function throws illegal escape exception

Question

I want to built a calculator which accepts numbers like 1E100 or 1.34E-200. In order to check if the number entered is acceptable i decided to test the condition with my regex:

                              ^-?\\d+\\.?\\d*\\E?\\-?\\d*$

however i get an illegal escape and i dont know why? does reges not accept my E?

Do not escape letters. Do not escape **word** characters in the regex when these chars are to be matched *literally*. Also, see [my answer](https://stackoverflow.com/a/43616524/3832970). — Wiktor Stribiżew, Jun 25 '20 at 09:42

score -1 · Answer 1 · answered Jun 25 '20 at 09:33

-1

You escaped the E, which is not necessary :

^(-?\d+\.?\d*E?\-?\d*)$

Test it here

answered Jun 25 '20 at 09:33

totok

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My regex function throws illegal escape exception

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