CODEWITHSUNDEEP
regex
Lesha Pipiev
Lesha Pipiev

Reputation: 3333

RegExp repeated groups

I have a string:

10-02;34-05;

Elements like dd-dd can be repeated many times:

10-02;34-05;12-02;23-05;10-42;44-05

At the end of the string the symbol ; can be optional but between elements dd-dd the symbol ; should be mandatory.

I tried ti build regular expression /^([0-9]{2}-[0-9]{2}[;])+$/) but it covers cases like 10-02;34-05;12-02;23-05;10-42;44-05 but not 10-02;34-05;12-02;23-05;10-42;44-05; with the symbol ; at the end.

How Do I have to build an regular expression to cover both of cases.

Thanks.

Upvotes: 2

Views: 561

Answers (4)

Bohemian
Bohemian

Reputation: 425428

This is about as simply/briefly as you can express it:

^(\d\d-\d\d(;|$))+$

Upvotes: 2

HamZa
HamZa

Reputation: 14931

Simple ^(?:\d{2}-\d{2}(?:;|$))+$

Which means:

^               # start of line
(?:             # non-capturing group
    \d{2}       # match 2 digits
    -           # match a hyphen
    \d{2}       # match 2 digits
    (?:;|$)     # match ; or end of line
)+              # repeat 1 or more times
$               # end of line

Note

10-02;34-05;12-012;23-05;10-42;44-05;
                ^--- You have 3 digits here ??? If so change all {2} to +

Online demo

Upvotes: 3

cgledezma
cgledezma

Reputation: 622

Use something like this:

^(\d{2}-\d{2};)*\d{2}-\d{2}(;)?$

The ?operator makes the last parenthized expression optional, like placing a {0, 1} after it.

Upvotes: 1

Anirudha
Anirudha

Reputation: 32827

You can use ? to optionally match a pattern

^\d{2}-\d{2}(;\d{2}-\d{2})*;?$

or

^(\d{2}-\d{2};)*(\d{2}-\d{2};?)$

Upvotes: 2

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