Regex for validate a number with some criteria

Question

I need to validate a number with those criterias :

1. Can be float or integer
2. Scale 4
3. Precision 2

I tried like this :

pattern="/^[-+]?[0-9]\d*(\.\d+)?$/i",

Some examples :

1. valid : 2; -1; 0.4; 0.12; 1928; 1827.78; -182.4
2. invalid : 10000; 0.345; 89374.5;

Thx in advance.

Answer 1

You may use

'/^[-+]?(?:[1-9]\d{0,3}|0)(?:\.\d{1,2})?$/'

See the regex demo.

Details

• ^ - start of string
• [-+]? - either - or +
• (?:[1-9]\d{0,3}|0) - a non-capturing group matching either
  • [1-9]\d{0,3} - a digit from 1 to 9 (non-zero) and any 0 to 3 digits
  • | - or
  • 0 - a zero
• (?:\.\d{1,2})? - an optional non-capturing group matching 1 or 0 occurrences of
  • \. - a dot
  • \d{1,2} - 1 or 2 digits
• $ - end of string.