Foreach: Get All The Keys That Have The Value "X"

arrays, foreach, php

Solution

If you would like all of the keys for a particular value, I would suggest using `array_keys`, using the optional `search_value` parameter.

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

Where `$result` becomes

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

If you wish to use a `foreach`, you can iterate through each key/value set, adding the key to a new array collection 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 
)

Problem

Suppose I have an array like this: ``` $array = array("a","b","c","d","a","a"); ``` and I want to get all the keys that have the value "a". I know I can get them using a `while` loop: ``` while ($a = current($array)) { if ($a == 'a') { echo key($array).','; } next($array); } ``` How can I get them using a `foreach` loop instead? I've tried: ``` foreach ($array as $a) { if ($a == 'a') { echo key($array).','; } } ``` and I got 1,1,1, as the result.

Original source