CODEWITHSUNDEEP
javaregex
jasilva
jasilva

Reputation: 750

Java regular expression empty or my format

Hello i have a regular expression that works [2-5][0-5]:[0-8][0-8] accepts numbers like 20:88, 35:14, 32:54, etc.

I use the anotattion javax.validation.constraints.Pattern to validate entities.

But I need to accept empty string or the format that I showed.

I tried [^.]|[2-5][0-5]:[0-8][0-8] [^.]|([2-5][0-5]:[0-8][0-8]) ^.|[2-5][0-5]:[0-8][0-8] (^.)|[2-5][0-5]:[0-8][0-8]

But not works. I tried put empty|myformat

Upvotes: 1

Views: 101

Answers (1)

Casimir et Hippolyte
Casimir et Hippolyte

Reputation: 89547

Try this:

^(?:[2-5][0-5]:[0-8][0-8])?$

(?:..) is a non capturing group and ? makes the group optional.

^ and $ are anchors for start and end of the string.

However, if your goal is to match a number between 20 and 55 for the first part and, 00 and 88 for the second part, then this pattern will do it better:

^(?:(?:[2-4][0-9]|5[0-5]):(?:[0-7][0-9]|8[0-8]))?$

Upvotes: 4

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