php index of item

Question

I have an array that looks like this:

$fruit = array('apple','orange','grape');

How can I find the index of a specific item, in the above array? (For example, the value 'orange')

Solution 1

Try the array_search function.

From the first example in the manual:

<?php
$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');

$key = array_search('green', $array); // $key = 2;
$key = array_search('red', $array);   // $key = 1;
?>

A word of caution

When comparing the result, make sure to test explicitly for the value false using the === operator.

Because arrays in PHP are 0-based, if the element you're searching for is the first element in the array, a value of 0 will be returned.

While 0 is a valid result, it's also a falsy value, meaning the following will fail:

<?php
    $array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');   

    $key = array_search('blue',$array);

    if($key == false) {
        throw new Exception('Element not found');
    }
?>

This is because the == operator checks for equality (by type-juggling), while the === operator checks for identity.

Solution 2

have in mind that, if you think that your search item can be found more than once, you should use array_keys() because it will return keys for all matching values, not only the first matching key as array_search().

Regards.

Comments

[mcgrailm]

Return Values Returns TRUE if needle is found in the array, FALSE otherwise.

[mcgrailm]

I think doing the if(in_array(. bit should protect me from the problme you noted after "be careful"

[Dmitry Gamolin]

There's a small error in the code, the array is not specified. It should be array_search('blue', $array).