PHP if in_array() how to get the key as well?

Struggling with a tiny problem.

I have an array:

Array
(
    [0] => 
    [6] => 6
    [3] => 5
    [2] => 7
)

I am checking if a set value is in the array.

if(in_array(5, $array)) {
//do something
} else {
// do something else
}

The thing is, when it find the value 5 in array, I really need the key to work with in my "do something".

In this case I need to set:

$key = 3;

(key from the found value in_array).

Any suggestions?

array_search() is what you are looking for.

if (false !== $key = array_search(5, $array)) {
    // found!
} else {
    // not found!
}

If you only need the key of the first match, use array_search():

$key = array_search(5, $array);
if ($key !== false) {
    // Found...
}

If you need the keys of all entries that match a specific value, use array_keys():

$keys = array_keys($array, 5);
if (count($keys) > 0) {
    // At least one match...
}

You could just use this http://www.php.net/manual/en/function.array-search.php

$key = array_search(5, $array)
if ($key !== false) {
...

You can try

if(in_array(5, $array))
{
    $key = array_search(5, $array);
    echo $key;
}

this way you know it exists, and if it doesn't it doesn't cause notices, warnings, or fatal script errors depending on what your doing with that key there after.

Maybe you want to use array_search instead, which returns false if the value is not found and the index if the value is found. Check out the description here

In case anyone need it in array of arrrays. My case was this:

I had an array like this:

$myArray =

array:3 [▼
  0 => array:3 [▼
	0 => 2
	1 => 0
	2 => "2019-07-21 23:59:59"
  ]
  1 => array:3 [▼
	0 => 3
	1 => 2
	2 => "2019-07-21 23:59:59"
  ]
  2 => array:3 [▼
	0 => 1
	1 => 1
	2 => "2019-07-21 23:59:59"
  ]
]

And another one like this (an array of objects):

$Array2 = 

Collection {#771 ▼
  #items: array:12 [▼
	0 => {#1047 ▼
	  +"id": 2
	  +"name": "demografico"
	  +"dict_key": "demographic"
	  +"component": "Demographic"
	  +"country_id": null
	  +"created_at": null
	  +"updated_at": null
	}
	1 => {#1041 ▶}
	2 => {#1040 ▶}
    etc...

As the OP, I had to "do something" (use values in a html php template, my case Laravel with blade) with the key where some value was in the array. For my code, I had to use this:

foreach($Array2 as $key => $item)
    if(false !== $key = array_search($item->id, array_column($myArray, 0))
    // Note that $key is overwritten
        <input type="number" class="form-control" id="{!! $item->id !!}" value="{{ $myArray[$key][1] }}">