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How to Sort an Array containing 1 to n values in PHP ?

In this article, we will see how to sort an array that contains 1 to n values in PHP. There are various approaches through which we can sort an array with custom values. Below is an example for a better understanding of the problem statement.

Example:

Input: arr = [3, 1, 4, 5, 2, 8, 9, 5]
Output: Sorted Array is: [1, 2, 3, 4, 5, 8, 9]
 
Input: arr = [3, 1, 4, 5, 2, 0, 10]
Output: Sorted Array is: [0, 1,  2, 3, 4, 5, 10]

There are two methods to sort an array that contains 1 to n values:

Table of Content

Using PHP sort() Function

We will use the built-in sort() function to sort the input array into ascending to descending order. It sorts the actual array and hence changes are reflected in the original array itself. 

Syntax

sort(array &$array, int $sort_flags = SORT_REGULAR): bool

Example: This example uses the built-in sort() function to sort the input array into the correct order.

PHP 
<?php
function sortArray($arr)
{
    sort($arr);
    return $arr;
}
$arr1 = [3, 1, 4, 5, 2, 8, 6, 10, 7];
$arr2 = [3, 1, 4, 5, 2, 0, 10];
$result1 = sortArray($arr1);
$result2 = sortArray($arr2);
echo "Sorted Array is: [" . implode(", ", $result1) . "]\n";
echo "Sorted Array is: [" . implode(", ", $result2) . "]\n";
?>

Output
Sorted Array is: [1, 2, 3, 4, 5, 6, 7, 8, 10]
Sorted Array is: [0, 1, 2, 3, 4, 5, 10]

Using a Custom Sorting Algorithm (Bubble Sort)

We will use the Bubble sort algorithm to manually sort the array without relying on any built-in approach to sort the array. Here, the loops are used to iterate over the array elements and sort them in the correct order.

Syntax

function bubbleSort(&$arr) {
    $n = count($arr);
    for ($i = 0; $i < $n - 1; $i++) {
        for ($j = 0; $j < $n - $i - 1; $j++) {
            if ($arr[$j] > $arr[$j + 1]) {
            
                // Swap $arr[$j] and $arr[$j+1]
                $temp = $arr[$j];
                $arr[$j] = $arr[$j + 1];
                $arr[$j + 1] = $temp;
            }
        }
    }
}

Example: This example uses the custom sorting algorithm (Bubble Sort) to sort the input array elements.

PHP 
<?php
function customSortArray($arr)
{
    $n = count($arr);
    for ($i = 0; $i < $n - 1; $i++) {
        for ($j = 0; $j < $n - $i - 1; $j++) {
            if ($arr[$j] > $arr[$j + 1]) {
                $temp = $arr[$j];
                $arr[$j] = $arr[$j + 1];
                $arr[$j + 1] = $temp;
            }
        }
    }
    return $arr;
}
$arr1 = [3, 1, 4, 5, 2, 8, 6, 10, 7];
$arr2 = [3, 1, 4, 5, 2, 0, 10];
$result1 = customSortArray($arr1);
$result2 = customSortArray($arr2);
echo "Sorted Array is: [" . implode(", ", $result1) . "]\n";
echo "Sorted Array is: [" . implode(", ", $result2) . "]\n";
?>

Output
Sorted Array is: [1, 2, 3, 4, 5, 6, 7, 8, 10]
Sorted Array is: [0, 1, 2, 3, 4, 5, 10]

Using a Custom Sorting Algorithm (Quicksort)

We will use the Quicksort algorithm to manually sort the array without relying on any built-in approach to sort the array. Quicksort is a divide-and-conquer algorithm that is efficient for large datasets.

PHP 
<?php
function quickSort(&$arr) {
    if(count($arr) < 2) {
        return $arr;
    }
    $left = $right = array();
    reset($arr);
    $pivot_key = key($arr);
    $pivot = array_shift($arr);
    foreach($arr as $k => $v) {
        if($v < $pivot)
            $left[$k] = $v;
        else
            $right[$k] = $v;
    }
    return array_merge(quickSort($left), array($pivot_key => $pivot), quickSort($right));
}
$arr1 = [3, 1, 4, 5, 2, 8, 6, 10, 7];
$arr2 = [3, 1, 4, 5, 2, 0, 10];
$result1 = quickSort($arr1);
$result2 = quickSort($arr2);
echo "Sorted Array is: [" . implode(", ", $result1) . "]\n";
echo "Sorted Array is: [" . implode(", ", $result2) . "]\n";
?>

Output
Sorted Array is: [1, 2, 3, 4, 5, 6, 7, 8, 10]
Sorted Array is: [0, 1, 2, 3, 4, 5, 10]

Using a Custom Sorting Algorithm (Insertion Sort)

Insertion Sort is a simple and efficient comparison-based sorting algorithm. It builds the final sorted array one item at a time, with each iteration removing an element from the input data and inserting it into the correct position in the already sorted part of the array.

Example: This example uses the custom sorting algorithm (Insertion Sort) to sort the input array elements.

PHP 
<?php
function insertionSort(&$arr) {
    $n = count($arr);
    for ($i = 1; $i < $n; $i++) {
        $key = $arr[$i];
        $j = $i - 1;

        // Move elements of $arr[0..$i-1], that are greater than $key, to one position ahead of their current position
        while ($j >= 0 && $arr[$j] > $key) {
            $arr[$j + 1] = $arr[$j];
            $j--;
        }
        $arr[$j + 1] = $key;
    }
}

$arr1 = [3, 1, 4, 5, 2, 8, 6, 10, 7];
$arr2 = [3, 1, 4, 5, 2, 0, 10];
insertionSort($arr1);
insertionSort($arr2);
echo "Sorted Array is: [" . implode(", ", $arr1) . "]\n";
echo "Sorted Array is: [" . implode(", ", $arr2) . "]\n";
?>

Output
Sorted Array is: [1, 2, 3, 4, 5, 6, 7, 8, 10]
Sorted Array is: [0, 1, 2, 3, 4, 5, 10]

Using Merge Sort

Merge Sort is a divide-and-conquer algorithm that recursively divides the array into halves, sorts each half, and then merges the sorted halves to produce a sorted array. Merge Sort is efficient for large datasets and has a time complexity of O(n log n).

Example:

PHP 
<?php
function mergeSort($arr) {
    if (count($arr) <= 1) {
        return $arr;
    }
    
    $mid = floor(count($arr) / 2);
    $left = array_slice($arr, 0, $mid);
    $right = array_slice($arr, $mid);
    
    $left = mergeSort($left);
    $right = mergeSort($right);
    
    return merge($left, $right);
}

function merge($left, $right) {
    $result = [];
    $i = 0;
    $j = 0;
    
    while ($i < count($left) && $j < count($right)) {
        if ($left[$i] < $right[$j]) {
            $result[] = $left[$i];
            $i++;
        } else {
            $result[] = $right[$j];
            $j++;
        }
    }
    
    while ($i < count($left)) {
        $result[] = $left[$i];
        $i++;
    }
    
    while ($j < count($right)) {
        $result[] = $right[$j];
        $j++;
    }
    
    return $result;
}

$arr = [3, 1, 4, 5, 2, 8, 9, 5];
$sortedArray = mergeSort($arr);

echo "Sorted Array is: ";
print_r($sortedArray);
?>

Output
Sorted Array is: Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 5
    [6] => 8
    [7] => 9
)




Reffered: https://www.geeksforgeeks.org

PHP

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Category:
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Sub Category:
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