Using of regex with preg_replace_callback

Question

I'd like to capitalize the first letter of a string which could have special characters (that's the reason ucfirst is not valid here). I have next code:

$string = 'ésta';
$pattern = '/^([^a-z]*)([a-z])/i';

$callback_fn = 'process';

echo preg_replace_callback($pattern, $callback_fn, $string);


function process($matches){
    return $matches[1].strtoupper($matches[2]);
}

which returns 'éSta' but 'Ésta' was expected... I think my problem is the pattern I'm using, but I have made different combinations (like $pattern = '/\pL/u') but I haven't found a good regex.

Elliot Chance · Accepted Answer · 2012-06-21 08:04:47Z

2

This is because your a-z will not match é. Writing a regex to encompass unicode characters may be difficult.

From your code it will only capitalise the first letter, regardless of the amount of words in your string. If so just do this:

$string = 'ésta';
$ucstring = ucphrase($string);

function ucphrase($word) {
  return mb_strtoupper(mb_substr($word, 0, 1)) . mb_substr($word, 1);
}

The mb_* functions should handle your special characters correctly.

Based on your comment below I understand your dilemma. In that case you can use your regular expression but with the correct unicode selectors

$string = 'ésta';
$pattern = '/(\p{L})(.+)/iu';

$callback_fn = 'process';

echo preg_replace_callback($pattern, $callback_fn, $string);


function process($matches){
    return mb_strtoupper($matches[1], 'UTF-8') . $matches[2];
}

edited Jun 21, 2012 at 8:04

answered Jun 21, 2012 at 7:37

Elliot Chance

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1 Comment

jprog Over a year ago

My problem is that it's not always the first letter wich I have to capitalize, because my string could be something like '¿"ésta"?' and I want my function to return '¿"Ésta"?'

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