Replace string in an array with PHP

Question

How can I replace a sub string with some other string for all items of an array in PHP?

I don't want to use a loop to do it. Is there a predefined function in PHP that does exactly that?

How can I do that on keys of array?

Answer 1

Why not just use str_replace without a loop?

$array = array('foobar', 'foobaz');
$out = str_replace('foo', 'hello', $array);

Answer 2

$array = array_map(
    function($str) {
        return str_replace('foo', 'bar', $str);
    },
    $array
);

But array_map is just a hidden loop. Why not use a real one?

foreach ($array as &$str) {
    $str = str_replace('foo', 'bar', $str);
}

That's much easier.

Answer 3

This is a very good idea that I found and used successfully:

function str_replace_json($search, $replace, $subject) 
{
    return json_decode(str_replace($search, $replace, json_encode($subject)), true);
}

It is good also for multidimensional arrays.

If you change the "true" to "false" then it will return an object instead of an associative array.

Source: Codelinks

Answer 4

I am not sure how efficient this is, but I wanted to replace strings in a big multidimensional array and did not want to loop through all items as the array structure is pretty dynamic.

I first json_encode the array into a string.

Replace all the strings I want (need to use preg_replace if there are non-English characters that get encoded by json_encode).

json_decode to get the array back.

Answer 5

function my_replace_array($array,$key,$val){
    for($i=0;$i<count($array);$i++){
        if(is_array($array[$i])){
            $array[$i] = my_replace_array($array[$i],$key,$val);
        }else{
            $array[$i]=str_replace($key,$val,$array[$i]);
        }
    }
    return $array;
}

Answer 6

With array_walk_recursive()

function replace_array_recursive( string $needle, string $replace, array &$haystack ){
    array_walk_recursive($haystack,
        function (&$item, $key, $data){
        $item = str_replace( $data['needle'], $data['replace'], $item );
        return $item;
    },
        [ 'needle' => $needle, 'replace' => $replace ]
    );
}

Answer 7

There is no predefined function anymore (since PHP 8.1). So this will replace in all elements, even if there are Objects:

<?php

class Arrays {
    /**
     * Replaces in all strings within a multidimensional array, even if objects are included
     * @param  string $search       search for this string
     * @param  string $replace_with replace with this string
     * @param  mixed $haystack        Array or Object to search in all elements
     * @return mixed               gives the same structure back
     */
    public static function replace_everywhere($search, $replace_with, $haystack) {
        if (is_array($haystack) or is_object($haystack)) {
            // Arrays and Objects
            foreach ($haystack as &$value) {
                $value = Arrays::replace_everywhere($search, $replace_with, $value);
            }
            return $haystack;
        } elseif (is_string($haystack)) {
            // replace in a string element
            return str_replace($search, $replace_with, $haystack);
        } else {
            // other datatypes (e.g. integer) stay untouched
            return $haystack;
        }
    }
}


// You can call this like e.g.
$a = array(true, 1, 'foo<bar', 'foo<baz', array("foo<loo"), (object) array('1' => 'foo<boo'));
$a = Arrays::replace_everywhere("<", "&lt;", $a);
var_export($a);

Example: https://3v4l.org/CDGvC#v8.2.5

---

If you want to replace array keys, I think that's another question with good answers like: recursively-change-keys-in-array

Answer 8

$base = array('citrus' => array( "orange") , 'berries' => array("blackberry", "raspberry"), );
$replacements = array('citrus' => array('pineapple'), 'berries' => array('blueberry'));
$basket = array_replace_recursive($base, $replacements);
$basket = array_replace($base, $replacements);