Decimal or numeric values in regular expression validation

Question

I am trying to use a regular expression validation to check for only decimal values or numeric values. But user enters numeric value, it don\'t be first digit \"0\"

Answer 1

Here is my regex for validating numbers:

^(-?[1-9]+\\d*([.]\\d+)?)$|^(-?0[.]\\d*[1-9]+)$|^0$

Valid numbers:

String []validNumbers={"3","-3","0","0.0","1.0","0.1","0.0001","-555","94549870965"};

Invalid numbers:

String []invalidNumbers={"a",""," ","-","001","-00.2","000.5",".3","3."," -1","--1","-.1","-0"};

Answer 2

Try this code, hope it will help you

String regex = "(\\d+)(\\.)?(\\d+)?";  for integer and decimal like 232 232.12 

Answer 3

Here is a great working regex for numbers. This accepts number with commas and decimals.

/^-?(?:\d+|\d{1,3}(?:,\d{3})+)?(?:\.\d+)?$/

Answer 4

/([0-9]+[.,]*)+/ matches any number with or without coma or dots

it can match

         122
         122,354
         122.88
         112,262,123.7678

bug: it also matches 262.4377,3883 ( but it doesn't matter parctically)