PHP INTERVIEW · Episode 07

Find a value in an array — then remove it

in_array(), array_search(), unset() and friends

ep7_array_search_and_remove.php

<?php
$fruits = ["Apple", "Banana", "Mango", "Kiwi"];

$toRemove = "Mango";
if(in_array($toRemove , $fruits)){
    $elementPosition =  array_search($toRemove , $fruits);
    /* using unset and re searilize array
    unset($fruits[$elementPosition]);
    $fruits = array_values($fruits);
    */
    /* one line statement */
    array_splice($fruits,$elementPosition,1);
}else{
 // echo "value not found";
}

Output

Output for this tutorial goes here.

Array
(
    [0] => Apple
    [1] => Banana
    [2] => Kiwi
)

The Question

Two everyday array tasks rolled into one question: first check whether a value is in the array, then remove it. Simple — until the interviewer asks about the edge cases.

Checking if it exists

in_array($needle, $array) returns true / false — use it when you only care whether the value is there.

array_search($needle, $array) returns the key of the first match (or false if missing) — use it when you need where the value is.

Removing it

unset($array[$key]) deletes the element but leaves a gap in the numeric keys. Follow it with array_values() to re-index (0, 1, 2…).

Shortcut: array_splice($array, $index, 1) removes and re-indexes in one step. To drop every matching value, use array_filter().

Example Output

in_array("Mango", $fruits) → true

array_search("Mango", $fruits) → 2

after removing →

AppleBananaKiwi

Key takeaway: in_array() answers yes/no, array_search() gives the key, and unset() + array_values() (or array_splice()) removes it cleanly.

The gotcha: array_search() can return 0 (a valid first index) or false (not found). Always test with !== false, never a loose if. And pass true as the third argument to both functions for a strict (type-safe) comparison.

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