CODEWITHSUNDEEP
javaregex
kamal
kamal

Reputation: 173

Regular Expression With Unique Digits

I am trying to create a regular expression with Unique digits separated with comma with max 5 digit and numbers are allowed from 1-10. for example

1,2,3,4,5 - valid

1,2,2,4,5 - Invalid (Because it's allowing to define duplicate digits)

but I want regular expression in which we can enter only unique number. I am mentioning below my regex which allow digits with comma separated and allow 5 digits between 1-10.

^([1-9]|10)(?:,([1-9]|10)){0,4}$

Please help how to define this regex which allow only unique digits

Upvotes: 2

Views: 503

Answers (1)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626738

You may use

^(?!.*\b(\d+)\b.*\b\1\b)(?:[1-9]|10)(?:,(?:[1-9]|10)){0,4}$

See an online regex demo.

The (?!.*\b(\d+)\b.*\b\1\b) negative lookahead fails any match if there are repeated identical digit chunks as whole words (enclosed with word boundary positions).

See the Java demo:

List<String> strs = Arrays.asList("1,2,3,4,5", "1,2,2,4,5");
String rx = "(?!.*\\b(\\d+)\\b.*\\b\\1\\b)(?:[1-9]|10)(?:,(?:[1-9]|10)){0,4}";
for (String str : strs)
    System.out.println(str + ": " + str.matches(rx));

Output:

1,2,3,4,5: true
1,2,2,4,5: false

Note that ^ and $ at the start and end of the pattern are omitted in Java code since .matches requires a full string match.

Upvotes: 2

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