PHP regex - valid float number

Question

I want user only input 0-9 and only once \".\"

 patt = /[^0-9(.{1})]/

 1.2222 -> true
 1.2.2  -> false (only once \'.\')

help me , t

Answer 1

/^-?(?:\d+|\d*\.\d+)$/

This matches normal floats e.g. 3.14, shorthands for decimal part only e.g. .5 and integers e.g. 9 as well as negative numbers.