CODEWITHSUNDEEP
phpregex
surz
surz

Reputation: 103

RegEx match string separated by space

I've to validate a string pattern representing 2-2 letter language codes (see FacebookLocales.xml):

$languages = 'af_ZA ak_GH am_ET ar_AR as_IN ay_BO az_AZ be_BY';

So far I could come up with this:

preg_match ( "/^([a-z]{2}_[A-Z]{2}\s)+$/", $languages );

This works fine if there's a trailing space, if the trailing space is removed then it returns 0;

Upvotes: 0

Views: 798

Answers (1)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626758

You can unroll your pattern like

'/^[a-z]{2}_[A-Z]{2}(?:\s+[a-z]{2}_[A-Z]{2})*$/'

or - to shorten the pattern a bit:

'/^([a-z]{2}_[A-Z]{2})(?:\s+\g<1>)*$/'

See the regex demo

The \g<1> recurses (repeats) the subpattern defined in the first capturing group (thus, it uses [a-z]{2}_[A-Z]{2} rather than the captured value as opposed to \1 backreference).

Upvotes: 1

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