PHP

PHP

πŸ“€ PHP array_shift() Function: Removing the First Element

The array_shift() function in PHP shifts the first value of the array off and returns it, shortening the array by one element and moving everything down.

  • Return Value: array_shift() returns the removed value. If the array is empty or not an array, it returns null.

πŸ› οΈ Basic Syntax & Usage

Pass an array variable to array_shift() to remove its beginning element:

PHP
$queue = ["First Task", "Second Task", "Third Task"];

// Shift the first element off the beginning
$currentTask = array_shift($queue);

echo "Processing: " . $currentTask; // Outputs: Processing: First Task

print_r($queue);
/*
Output:
Array
(
    [0] => Second Task
    [1] => Third Task
)
*/

πŸ”„ Queue (FIFO) Operations with PHP

Combining array_push() and array_shift() allows you to easily implement a standard First-In, First-Out (FIFO) queue structure in PHP.

PHP
$customerQueue = [];

// Customers join queue
array_push($customerQueue, "John");
array_push($customerQueue, "Sarah");

// Serve first customer in line (Shift first item)
$servedCustomer = array_shift($customerQueue); // "John"

echo "Served: " . $servedCustomer;
echo " Next in line: " . $customerQueue[0]; // "Sarah"

πŸ“‹ Key Rules & Behaviors

  • 1. Index Re-indexing: All numerical keys will be modified to start counting from zero (0), while literal string keys will remain untouched.
  • 2. Direct Mutation: The function directly modifies the target array variable passed into it by reference.
  • 3. Empty Array Handling: Calling array_shift() on an empty array safely returns null without producing errors.

πŸ“Š Array Beginning/End Removal Comparison

Function Target Position Key Re-indexing Common Data Structure
array_pop() End of array No (Keys stay as they are) Stack (LIFO)
array_shift() Beginning of array Yes (Numeric keys reset from 0) Queue (FIFO)

  • πŸ“ Short Summary

  • array_shift() removes and returns the first element from an array.
  • It automatically updates numeric keys so the remaining elements re-index starting from 0.
  • Use array_shift() along with array_push() to handle FIFO queues.
PHP array_pop()
PHP array_unshift()