PHP - preg_replace items in brackets with array items

Question

I have an array:

array('id' => 'really')

I have a string:

$string = 'This should be {id} simple.';

I want to end up with:

This should be really simple.

I have a regular expression that will work with the {id} aspect, but I am having a hard time doing what I want.

/{([a-zA-Z\_\-]*?)}/i

{id} could be anything, {foo} or {bar} or anything that matches my regular expression.

I am sure that there is a simple solution that is escaping me at the moment.

Thanks,

Justin

Ultimately, I'd refactor this whole task and leverage vprintf(). — mickmackusa
– mickmackusa ♦, Commented Jul 31, 2022 at 3:08

kodeart · Accepted Answer · 2014-02-05 20:08:52Z

4

str_replace is faster then preg_replace, try this:

$arr = array('a' => 'a', 'b' => 'b');
$str = "{a} {b} {c}";
$values = array_values($arr);
$keys = array_keys($arr);

foreach ($keys as $k => $v) {
    $keys[$k] = '{'.$v.'}';
}

str_replace($keys, $values, $str);

edited Feb 5, 2014 at 20:08

kodeart

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answered Dec 16, 2010 at 3:19

Stuck

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2 Comments

manumoomoo Over a year ago

This is true, but $arr (in your example) could have 100's of key/value pairs, I wonder if your solution would still be faster. Thanks.

Stuck Over a year ago

maybe you can build the $arr in a way that it directly contains the '{' and '}? then you don't need the extra loop. But anyway.. it's still O(n) ;-) If you don't need fancy replacing rules , you should always use this function instead of ereg_replace() or preg_replace(). see: php.net/manual/en/function.str-replace.php

codaddict · Accepted Answer · 2010-12-16 04:07:10Z

4

You can use the preg_replace with e modifier as:

$string = preg_replace('/{([a-zA-Z\_\-]*?)}/ie','$arr["$1"]',$string);

Ideone Link

Using the e modifier you can have any PHP expression in the replacement part of preg_replace.

Now why did your regex /{([a-zA-Z\_\-])*?}/i not work?

You've put *? outside the capturing parenthesis ( ) as a result you capture only the first character of the word found in { }.

Also note that you've not escaped { and } which are regex meta-character used for specifying range quantifier {num}, {min,max}. But in your case there is no need to escape them because the regex engine can infer from the context that { and } cannot be used as range operator as they are not having numbers in required format inside them and hence treats them literally.

answered Dec 16, 2010 at 4:07

codaddict

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3 Comments

manumoomoo Over a year ago

thanks for the updates to my regex and the other helpful hints. Silly mistake really. Thanks, again.

kodeart Over a year ago

\e modifier is deprecated as of v5.5

mickmackusa Over a year ago

Please update this unusable snippet. e doesn't work. i doesn't make sense. Underscores don't need to be escaped in a character class. The ideone links is dead.

Community · Accepted Answer · 2020-06-20 09:12:55Z

1

preg_replace_callback has a callback option which make that kind of things possible.

function replaceText($matches){
  global $data;
  return $data[$matches[1]];
}
preg_replace_callback(
        '/{([a-zA-Z\_\-])*?}/i',
        'replaceText',
        $content
);

If you don't want to use the global variable create an class and use the array($object, 'method') callback notation.

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Dec 16, 2010 at 3:12

RageZ

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2 Comments

manumoomoo Over a year ago

Thanks. I forgot about preg_replace_callback.

mickmackusa Over a year ago

The i flag is useless because you have written a-zA-Z. _ doesn't need to be escaped inside of a character class.

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