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

This regex:

\d*(?:\.\d+)?

will give results:

123 -> true
123.345 -> true
123. -> true
.345 -> true
0.3345 -> true

However, you must check emptiness of the input before using it because the regex also permit zero-length input.