How to Sort an Array containing 1 to n values in PHP ?
Last Updated :
16 Jul, 2024
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:
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(", ", $result2) . "]\n";
?>
OutputSorted Array is: [1, 2, 3, 4, 5, 6, 7, 8, 10]
Sorted Array is: [0, 1, 2, 3, 4, 5, 10]
Using a Custom Sorting Algorithm (Bubble Sort)
We will use the Bubble sort algorithm to manually sort the array without relying on any built-in approach to sort the array. Here, the loops are used to iterate over the array elements and sort them in the correct order.
Syntax
function bubbleSort(&$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(", ", $result2) . "]\n";
?>
OutputSorted Array is: [1, 2, 3, 4, 5, 6, 7, 8, 10]
Sorted Array is: [0, 1, 2, 3, 4, 5, 10]
Using a Custom Sorting Algorithm (Quicksort)
We will use the Quicksort algorithm to manually sort the array without relying on any built-in approach to sort the array. Quicksort is a divide-and-conquer algorithm that is efficient for large datasets.
PHP
<?php
function quickSort(&$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(", ", $result2) . "]\n";
?>
OutputSorted Array is: [1, 2, 3, 4, 5, 6, 7, 8, 10]
Sorted Array is: [0, 1, 2, 3, 4, 5, 10]
Using a Custom Sorting Algorithm (Insertion Sort)
Insertion Sort is a simple and efficient comparison-based sorting algorithm. It builds the final sorted array one item at a time, with each iteration removing an element from the input data and inserting it into the correct position in the already sorted part of the array.
Example: This example uses the custom sorting algorithm (Insertion Sort) to sort the input array elements.
PHP
<?php
function insertionSort(&$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(", ", $arr2) . "]\n";
?>
OutputSorted Array is: [1, 2, 3, 4, 5, 6, 7, 8, 10]
Sorted Array is: [0, 1, 2, 3, 4, 5, 10]
Using Merge Sort
Merge Sort is a divide-and-conquer algorithm that recursively divides the array into halves, sorts each half, and then merges the sorted halves to produce a sorted array. Merge Sort is efficient for large datasets and has a time complexity of O(n log n).
Example:
PHP
<?php
function mergeSort($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);
?>
OutputSorted Array is: Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
[5] => 5
[6] => 8
[7] => 9
)
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