Clever Geek Handbook

Foreach: get all keys that have the value "X"

Suppose I have an array like this:

$array = array("a","b","c","d","a","a");

and I want to get all keys that have the value "a".

I know I can use them with a loop while

:

while ($a = current($array)) {
    if ($a == 'a') {
        echo key($array).',';
    }
    next($array);
}

How can I use them instead of a loop foreach

?

I tried:

   foreach ($array as $a) {
        if ($a == 'a') {
            echo key($array).',';
        }

    }

and i got

1,1,1,

...

+3


source to share


4 answers


If you want to use all keys for a specific value, I would suggest using array_keys

using an optional parameter search_value

.

$input = array("Foo" => "X", "Bar" => "X", "Fizz" => "O");
$result = array_keys( $input, "X" );

Where $result

becomes

Array ( 
  [0] => Foo 
  [1] => Bar 
)


If you want to use foreach

, you can iterate over each key / value set by adding the key to a new collection of the array when its value matches your search:

$array = array("a","b","c","d","a","a");
$keys = array();

foreach ( $array as $key => $value )
  $value === "a" && array_push( $keys, $key );

Where $keys

becomes

Array ( 
  [0] => 0 
  [1] => 4 
  [2] => 5 
)
+5


source


You can use below to print keys with special meaning




foreach ($array as $key=>$val) {
        if ($val == 'a') {
            echo $key." ";
        }

    }
+1


source


using

foreach($array as $key=>$val)
{
  //access the $key as key.
}
0


source


here's a simpler filter.

$query = "a";
$result = array_keys(array_filter($array,
    function($element)use($query){
        if($element==$query) return true;
    }
));
0


source






More articles:


All Articles