CODEWITHSUNDEEP
javaregex
Oleg Vazhnev
Oleg Vazhnev

Reputation: 24067

How to type ":" ("colon") in regexp?

: ("colon") has a special meaning in regexp, but I need to use it as is, like [A-Za-z0-9.,-:]*. I have tried to escape it, but this does not work [A-Za-z0-9.,-\:]*

Upvotes: 78

Views: 153571

Answers (4)

Bart Kiers
Bart Kiers

Reputation: 170237

In most regex implementations (including Java's), : has no special meaning, neither inside nor outside a character class.

Your problem is most likely due to the fact the - acts as a range operator in your class:

[A-Za-z0-9.,-:]*

where ,-: matches all ascii characters between ',' and ':'. Note that it still matches the literal ':' however!

Try this instead:

[A-Za-z0-9.,:-]*

By placing - at the start or the end of the class, it matches the literal "-". As mentioned in the comments by Keoki Zee, you can also escape the - inside the class, but most people simply add it at the end.

A demo:

public class Test {
    public static void main(String[] args) {
        System.out.println("8:".matches("[,-:]+"));      // true: '8' is in the range ','..':'
        System.out.println("8:".matches("[,:-]+"));      // false: '8' does not match ',' or ':' or '-'
        System.out.println(",,-,:,:".matches("[,:-]+")); // true: all chars match ',' or ':' or '-'
    }
}

Upvotes: 124

user456814
user456814

Reputation:

Colon does not have special meaning in a character class and does not need to be escaped. According to the PHP regex docs, the only characters that need to be escaped in a character class are the following:

All non-alphanumeric characters other than \, -, ^ (at the start) and the terminating ] are non-special in character classes, but it does no harm if they are escaped.

For more info about Java regular expressions, see the docs.

Upvotes: 6

SteeveDroz
SteeveDroz

Reputation: 6136

Be careful, - has a special meaning with regexp. In a [], you can put it without problem if it is placed at the end. In your case, ,-: is taken as from , to :.

Upvotes: 11

Anantha Sharma
Anantha Sharma

Reputation: 10108

use \\: instead of \:.. the \ has special meaning in java strings.

Upvotes: -3

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