Use a regex match as an array pointer - php

Question

I want to replace some numbers in a string with the content of the array in the position which this number points to.
For example, replace "Hello 1 you are great", with "Hello myarray[1] you are great"
I was doing the next: preg_replace('/(\d+)/','VALUE: ' . $array[$1],$string);
But it does not work. How could I do it?

Answer 1

You should use a callback.
<?php
$str = 'Hello, 1!';
$replacements = array(
1 => 'world'
);
$str = preg_replace_callback('/(\d+)/', function($matches) use($replacements) {
if (array_key_exists($matches[0], $replacements)) {
return $replacements[$matches[0]];
} else {
return $matches[0];
}
}, $str);
var_dump($str); // 'Hello, world!'
Since you are using a callback, in the event that you actually want to use a number, you might want to encode your strings as {1} or something instead of 1. You can use a modified match pattern:
<?php
// added braces to match
$str = 'Hello, {1}!';
$replacements = array(
1 => 'world'
);
// added braces to regex
$str = preg_replace_callback('/\{(\d+)\}/', function($matches) use($replacements) {
if (array_key_exists($matches[1], $replacements)) {
return $replacements[$matches[1]];
} else {
// leave string as-is, with braces
return $matches[0];
}
}, $str);
var_dump($str); // 'Hello, world!'
However, if you are always matching known strings, you may want to use #ChrisCooney's solution because it offers less opportunity to screw up the logic.

Answer 2

The other answer is perfectly fine. I managed it this way:
$val = "Chris is 0";
// Initialise with index.
$adj = array("Fun", "Awesome", "Stupid");
// Create array of replacements.
$pattern = '!\d+!';
// Create regular expression.
preg_match($pattern, $val, $matches);
// Get matches with the regular expression.
echo preg_replace($pattern, $adj[$matches[0]], $val);
// Replace number with first match found.
Just offering another solution to the problem :)

Answer 3

$string = "Hello 1 you are great";
$replacements = array(1 => 'I think');
preg_match('/\s(\d)\s/', $string, $matches);
foreach($matches as $key => $match) {
// skip full pattern match
if(!$key) {
continue;
}
$string = str_replace($match, $replacements[$match], $string);
}

Answer 4

<?php
$array = array( 2 => '**', 3 => '***');
$string = 'lets test for number 2 and see 3 the result';
echo preg_replace_callback('/(\d+)/', 'replaceNumber', $string);
function replaceNumber($matches){
global $array;
return $array[$matches[0]];
}
?>
output
lets test for number ** and see *** the result