Arrays in PHP

What are Arrays in PHP?

• Arrays in PHP provide a convenient way to store multiple values under a single variable.
• Arrays allow us to access and manipulate elements based on their index position.
• Arrays can hold various types of data, including numbers, strings, objects, and even other arrays.

Types of Arrays in PHP

• Indexed Array
• Associate Array
• Multi-dimensional Array

PHP Indexed Array

• An indexed array, also known as a numeric array, is the simplest and most common type of array.
• In an indexed array, each element is assigned a numeric index starting from zero.
• Let's consider an example of an indexed array representing a list of fruits:

1<?php
2// Define the array of fruits
3$fruits = array("apple", "banana", "orange");
4
5// Print the array 
6print_r($fruits);
7?>
8

• we create an indexed array named $fruits containing three elements.
• To access individual elements, we use their corresponding index. For instance, to retrieve the second element, we would use $fruits[1].

PHP Associate Array

• An associate array, also referred to as a key-value pair array, allows us to associate values with specific keys or names.
• Unlike indexed arrays, the elements in an associate array are not accessed by numeric indexes but rather by their assigned keys.
• To better understand this, let's look at an illustration:

1<?php
2// Define an associative array with student information
3$student = array(
4  "name" => "Sehaj Bindra",
5  "age" => 20,
6  "university" => "ABC University"
7);
8
9// Access and print specific elements of the array
10echo "Student Name: " . $student["name"] . "<br>";
11echo "Student Age: " . $student["age"] . "<br>";
12echo "University: " . $student["university"];
13?>

PHP Multi-dimensional Array

• A multi-dimensional array is an array that contains other arrays as its elements.
• It allows us to represent complex data structures such as matrices, tables, and grids.
• Let's consider an example of a two-dimensional array representing a tic-tac-toe board:

1<?php
2// Define a 2D array representing the tic-tac-toe board
3$board = array(
4  array("X", "O", "X"),
5  array("O", "X", "O"),
6  array("X", "O", "X")
7);
8
9// Loop through the rows and columns to print the board
10for ($i = 0; $i < 3; $i++) {
11  for ($j = 0; $j < 3; $j++) {
12    echo $board[$i][$j] . " ";
13  }
14  echo "<br>";
15}
16?>

1X O X 
2O X O 
3X O X 
4

Array Predefined Functions

• count ()
• array_push()
• array_merge()
• array_pop()

count()

• The count() function gives the array's total number of elements.
• When we need to determine the size of an array dynamically, it is especially helpful. Here's an illustration:

1$numbers = array (1, 2, 3, 4, 5);
2$count = count($numbers);
3echo "The array's size is given as: " . $count;

array_push()

• The array_push() function allows us to add one or more elements to the end of an array.
• It is commonly used to append new items to an existing array. Consider the following code snippet:

1$fruits = array("apple", "banana");
2array_push($fruits, "orange", "mango");
3print_r($fruits);

array_merge()

• A single array is created by combining two or more arrays using the array_merge() function.
• It is convenient when we are required to combine the contents of several arrays. Here's an illustration:

1<?php
2// Define the first array
3$first = array("apple", "banana");
4
5// Define the second array
6$second = array("orange", "mango");
7
8// Merge the two arrays
9$merged = array_merge($first, $second);
10
11// Print the merged array
12print_r($merged);
13?>

array_pop()

• The array_pop() function eliminates the final element of an array and returns it.
• It is frequently used for the last-in, first-out (LIFO) sequence of element extraction and processing. Here's an illustration:

1$fruits = array("apple", "banana", "orange");
2$lastFruit = array_pop($fruits);
3echo "The last fruit is: " . $lastFruit;

1The last fruit is: orange

Conclusion