Question

I have a string which contains several keywords in square backets which I want to identify, extract, and replace with something else:

For example:

‘You will win [winnings] or [slice].’

I want to identify all the terms within the squares, take those terms and replace them with certain values.

So it should end up like this:

‘You will win 100 or 95%.’

Any ideas?

Answer 1

$replacements = array(
    'winnings' => '100'
    , 'slice'  => '95%'
    , 'foobar' => 'Sean Bright'
);

$subject = '[foobar], You will win [winnings] or [slice]!';

$result = preg_replace_callback(
    '/\[([^\]]+)\]/',
    function ($x) use ($replacements) {
        if (array_key_exists($x[1], $replacements))
            return $replacements[$x[1]];
        return '';
    },
    $subject);

echo $result;

Note that this will completely fall apart if you have unbalanced brackets (i.e. [[foo])

For PHP versions less than 5.3:

$replacements = array(
    'winnings' => '100'
    , 'slice'  => '95%'
    , 'foobar' => 'Sean Bright'
);

function do_replacement($x)
{
    global $replacements;

    if (array_key_exists($x[1], $replacements))
        return $replacements[$x[1]];
    return '';
}

$subject = '[foobar], You will win [winnings] or [slice]!';

$result = preg_replace_callback(
    '/\[([^\]]+)\]/',
    'do_replacement',
    $subject);

echo $result;