CODEWITHSUNDEEP
javaregex
Maverick
Maverick

Reputation: 3053

Regular Expression to check alphanumeric with decimals but reject only alphanumeric, alphabet or numeric

Need help in forming regular expression to match text's having pure decimals or alphanumeric decimals but ignoring texts with the only alphanumeric without a decimal or only numeric value or only alphabets.

I tried this ^[a-zA-Z0-9]*[0-9.]*[0-9]$ but it is accepting even alphanumeric values.

Below are the test results which I am expecting.

Text Result
Test false
Test1 false
123 false
123.12.12 true
Test12.123 true

Upvotes: 0

Views: 1027

Answers (2)

Arvind Kumar Avinash
Arvind Kumar Avinash

Reputation: 79035

You can use the regex, \p{Alnum}+(?:\.\p{Alnum}+)+ which can be explained as follows:

  1. \p{Alnum} specifies an alphanumeric character:[\p{Alpha}\p{Digit}]
  2. (?:\.\p{Alnum}+)+ specifies a non-capturing group consisting of a dot followed by one or more alphanumeric characters. The non-capturing group must occur one or more times.

Demo:

public class Main {
    public static void main(String[] args) {
        String[] arr = { "Test", "Test1", "123", "123.12.12", "Test12.123", "123.123Test", "Test123.123Test",
                "Test123.12.12Test" };
        String regex = "\\p{Alnum}+(?:\\.\\p{Alnum}+)+";
        for (String s : arr) {
            System.out.println(s + " => " + (!s.matches(regex) ? "false" : "true"));
        }
    }
}

Output:

Test => false
Test1 => false
123 => false
123.12.12 => true
Test12.123 => true
123.123Test => true
Test123.123Test => true
Test123.12.12Test => true

Upvotes: 1

The fourth bird
The fourth bird

Reputation: 163277

You might use a lookahead to make sure that there is at least a single digit, and repeat matching 1 or more times the dot.

^(?=[A-Za-z]*[0-9])[A-Za-z0-9]+(?:\.[A-Za-z0-9]+)+$
  • ^ Start of string
  • (?=[A-Za-z]*[0-9]) Assert a digit
  • [A-Za-z0-9]+ Match 1+ times any of the listed ranges
  • (?:\.[A-Za-z0-9]+)+ Repeat 1 or more times a dot and again 1 or more of the listed ranges
  • $ End of string

Regex demo

Upvotes: 2

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