Array sort functions in PHP - Step-by-Step Execution

Concept Flow - Array sort functions

Start with array

↓

Choose sort function

↓

Compare elements

↓

Swap if needed

↓

Repeat until sorted

↓

Return sorted array

The array is sorted by repeatedly comparing and swapping elements until the whole array is ordered.

Execution Sample

PHP

<?php
$arr = [3, 1, 4, 2];
sort($arr);
print_r($arr);
?>

Sorts the array in ascending order and prints the sorted array.

Execution Table

Step	Array State	Action	Explanation	Output
1	[3, 1, 4, 2]	Start sorting	Initial array before sorting
2	[1, 3, 4, 2]	Swap 3 and 1	3 > 1, swap to order ascending
3	[1, 3, 4, 2]	Compare 3 and 4	3 < 4, no swap
4	[1, 3, 2, 4]	Swap 4 and 2	4 > 2, swap to order ascending
5	[1, 2, 3, 4]	Swap 3 and 2	3 > 2, swap to order ascending
6	[1, 2, 3, 4]	Array sorted	No more swaps needed	[1, 2, 3, 4]

💡 Array is fully sorted in ascending order, sort() function ends.

Variable Tracker

Variable	Start	After Step 2	After Step 4	After Step 5	Final
arr	[3, 1, 4, 2]	[1, 3, 4, 2]	[1, 3, 2, 4]	[1, 2, 3, 4]	[1, 2, 3, 4]

Key Moments - 3 Insights

Why does the array change after some steps but not others?

Only when two elements are out of order does the sort function swap them, as shown in steps 2, 4, and 5 in the execution_table.

Does sort() change the original array or create a new one?

sort() changes the original array in place, which you can see in variable_tracker where 'arr' updates after swaps.

Why is the output empty until the last step?

The output is only shown after sorting completes; intermediate steps show array changes but no output until the final sorted array is printed.

Visual Quiz - 3 Questions

Look at the execution_table at step 2, what is the array state?

A [3, 1, 4, 2]

B [1, 3, 4, 2]

C [1, 2, 3, 4]

D [3, 4, 1, 2]

💡 Hint

Check the 'Array State' column at step 2 in the execution_table.

At which step does the array become fully sorted?

A Step 4

B Step 5

C Step 6

D Step 3

💡 Hint

Look for the step where 'Array sorted' is noted in the 'Action' column.

If the initial array was [5, 4, 3, 2], what would happen at step 2?

A Swap 5 and 4

B No swap, array stays the same

C Swap 4 and 3

D Array is already sorted

💡 Hint

Refer to how sort swaps elements when the left is greater than the right in the execution_table steps.

Concept Snapshot

PHP array sort functions:
- Use sort() to sort arrays ascending.
- sort() changes the original array.
- Elements are compared and swapped until sorted.
- Output is the sorted array.
- Works with numbers and strings.

Full Transcript

This visual shows how PHP's sort() function works step-by-step. We start with an array of numbers. The function compares pairs of elements and swaps them if they are out of order. This process repeats until the whole array is sorted in ascending order. The variable 'arr' changes after each swap, showing the array's new order. The output is only shown after sorting completes. This helps beginners see how sorting rearranges elements inside the original array.