Linear Search Algorithm in PHP - Explanation, Example and Code

The Linear Search algorithm is a basic and straightforward search method. It works by iterating through each element of a sequence to find a specific value. While simple, this method is effective for small sequences or when the sequence is already sorted.

How It Works

  1. Iterate Through Elements: Start from the first element and check if the current value matches the target value.
  2. Check for Match: If the value at the current position matches the target value, the search process ends, and the position of the value is returned.
  3. Move to Next Element: If no match is found, move to the next element and continue checking.
  4. Repeat: Repeat steps 2 and 3 until the value is found or the entire sequence is traversed.

Example: Linear Search for the Number 7 in an Array

function linearSearch($arr, $target) {
    $n = count($arr);
    for ($i = 0; $i < $n; $i++) {
        if ($arr[$i] == $target) {
            return $i; // Return the position of the value
    return -1; // Value not found

$array = [2, 5, 8, 12, 15, 7, 20];
$targetValue = 7;

$result = linearSearch($array, $targetValue);

if ($result != -1) {
    echo "Value $targetValue found at position $result.";
} else {
    echo "Value $targetValue not found in the array.";

In this example, we use the Linear Search method to find the value 7 in the given array. We iterate through each element of the array and compare it with the target value. When we find the value 7 at the 5th position, the program returns the message "Value 7 found at position