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What is an Array in PHP?

An array is a special variable that can hold multiple values in a single variable. Instead of creating many variables, an array helps to store and organize data efficiently.

Types of Arrays in PHP

There are three main types of arrays in PHP:

  1. Indexed Arrays – Arrays with numeric indexes.

  2. Associative Arrays – Arrays with named keys.

  3. Multidimensional Arrays – Arrays containing one or more arrays inside them.

1. Indexed Arrays

An indexed array in PHP is an array where elements are stored with numeric indices (starting from 0 by default). It can be created using the array() function or the shorthand [] syntax. Elements in an indexed array can be accessed using their index number.

Indexed arrays can be created in two ways:

  1. Using array() function
  2. Using [] (short syntax)

Example 1: Creating an Indexed Array

<?php
// Creating an indexed array using array() function
$fruits = array("Apple", "Banana", "Cherry");

// Creating an indexed array using short syntax
$vegetables = ["Carrot", "Potato", "Spinach"];

// Accessing elements
echo $fruits[0]; // Outputs: Apple
echo $vegetables[2]; // Outputs: Spinach
?>

Example 2: Looping Through an Indexed Array

<?php
$colors = ["Red", "Green", "Blue"];

// Using for loop
for ($i = 0; $i < count($colors); $i++)
{
    echo $colors[$i] . "<br>";
}

// Using foreach loop
foreach ($colors as $color) 
{
    echo $color . "<br>";
}
?>

Example 3: Adding and Removing Elements

<?php
$numbers = [10, 20, 30];

// Adding elements
$numbers[] = 40;  // Adds 40 at the end
array_push($numbers, 50, 60); // Adds multiple elements

// Removing the last element
array_pop($numbers);

// Removing a specific element
unset($numbers[1]); // Removes the element at index 1

// Re-indexing the array
$numbers = array_values($numbers);

print_r($numbers);
?>

2. Associative Arrays

An associative array in PHP is an array where keys are strings instead of numeric indices. This allows storing data in key-value pairs for better readability and accessibility.

Example: Various operations on Associative Arrays

<?php
// 1. Creating an Associative Array
$student = [
    "name" => "John",
    "age" => 25,
    "course" => "PHP"
];

// 2. Accessing Elements
echo "Name: " . $student["name"] . "<br>";
echo "Age: " . $student["age"] . "<br>";

// 3. Adding Elements
$student["grade"] = "A";
echo "Added Grade: " . $student["grade"] . "<br>";

// 4. Updating Elements
$student["age"] = 26;
echo "Updated Age: " . $student["age"] . "<br>";

// 5. Removing an Element
unset($student["course"]);
echo "After removing course:<br>";
print_r($student);
echo "<br>";

// 6. Checking if a Key Exists
if (array_key_exists("name", $student)) {
    echo "Key 'name' exists in the array.<br>";
}

// 7. Looping Through an Associative Array
echo "Student Details:<br>";
foreach ($student as $key => $value) {
    echo "$key: $value <br>";
}

// 8. Getting All Keys and Values
$keys = array_keys($student);
$values = array_values($student);
echo "Keys: ";
print_r($keys);
echo "<br>Values: ";
print_r($values);
echo "<br>";

// 9. Sorting Operations
asort($student); // Sort by values (ascending)
echo "Sorted by Values (Ascending):<br>";
print_r($student);
echo "<br>";

ksort($student); // Sort by keys (ascending)
echo "Sorted by Keys (Ascending):<br>";
print_r($student);
echo "<br>";

// 10. Merging Two Associative Arrays
$extraInfo = ["city" => "New York", "country" => "USA"];
$student = array_merge($student, $extraInfo);
echo "After Merging:<br>";
print_r($student);
echo "<br>";

// 11. Counting Elements
echo "Total Elements in Array: " . count($student) . "<br>";
?>

3. Multidimensional Arrays

A multidimensional array in PHP is an array that contains one or more arrays as elements. It is used to store data in a tabular (row-column) format.

Types of Multidimensional Arrays:

  1. Two-Dimensional Arrays: A 2-dimensional array in PHP is an array that contains arrays as its elements, allowing you to represent data in a table-like structure (rows and columns).
  2. Three-Dimensional Arrays: A 3-dimensional array in PHP is an array that contains arrays of arrays, allowing you to represent data in a more complex structure (like a cube of data).

Example 1: Two-Dimensional Array

<?php
$students = [
    ["John", 25, "PHP"],
    ["Alice", 23, "Java"],
    ["Bob", 24, "Python"]
];

// Accessing elements
echo $students[0][0]; // Outputs: John
echo $students[1][2]; // Outputs: Java
?>

 Example 2: 

<?php
// Creating a multidimensional array
$students = array(
    array("John", 20, "PHP"),
    array("Sara", 22, "JavaScript"),
    array("Mike", 19, "Python")
);

// Accessing elements
echo $students[0][0]; // Outputs: John

// Looping through a multidimensional array
foreach ($students as $student) {
    echo "Name: " . $student[0] . " - Age: " . $student[1] . " - Course: " . $student[2] . "<br>";
}
?>

 


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