I want to add a key in the multidimensional array using the array_map() function.
$keywords = [['keyword'=>'designing'],['keyword'=>'logo designing']];
$user_id = 5;
$keywords = array_map(function($arr){
return $arr + ['user_id' => $user_id];
}, $keywords);
I want the output as
$keywords = [['user_id'=>5,'keyword'=>'designing'],['user_id'=>5,'keyword'=>'logo designing']];
but it's showing undefined variable $user_id.
The variable $user_id is not known in the anonymous function passed as the first argument to array_map().
You can easily solve this by using the use keyword that lets the function inherit the $user_id variable defined in the parent context.
$keywords = [['keyword'=>'designing'],['keyword'=>'logo designing']];
$user_id = 5;
$keywords = array_map(function($arr) use ($user_id) {
return $arr + ['user_id' => $user_id];
}, $keywords);
Add a simple use statement:
$keywords = array_map(function($arr) use ($user_id) {
return $arr + ['user_id' => $user_id];
}, $keywords);
Modify rows by reference and pass in the user_id value as the third parameter of array_walk(). (Demo)
array_walk($keywords, fn(&$v, $k, $u) => $v = ['user_id' => $u] + $v, $user_id);
Or with arrow functions, you can pass the user_id value without relying on use(). (Demo)
var_export(
array_map(fn($v) => ['user_id' => $user_id] + $v, $keywords)
);