Regular expression for floating point number Java

Question

I want to ask Regular expression

I have aa float number called 0.11,

in this case, the first digit must be Zero

and there can be at most three decimal digits , like 0.1, 0.11, 0.111

In Java, I code like this

String phone_regex = "d{1,1}.d{1,3}";

But it does not work...

Can someone provide some suggestion for me?

thank you

Answer 1

Try escaping your digit character group \\\\d , eg,

"^0\\.\\d{1,3}$"

This matches all strings beginning with a 0 , followed by a dot and 1-3 digits.

^ means beginning of line, $ means end of line. See also java.util.Pattern .

Answer 2

You need to escape the numbers class ( \\d ) and the . char.

String phone_regex = "\\d\\.\\d{1,3}";