PHP Array

PHP arrays are flexible and powerful data structures that allow you to store multiple values in a single variable. They can hold different types of values such as integers, strings, or even other arrays. There are three main types of arrays in PHP:

1. Indexed Arrays: Arrays with a numeric index.
2. Associative Arrays: Arrays where the keys are named.
3. Multidimensional Arrays: Arrays containing one or more arrays.

Let's explore each type with examples and outputs.

Indexed Arrays

Indexed arrays use numeric indices to access their values.

<?php
$fruits = array("Apple", "Banana", "Cherry");

// Accessing values
echo $fruits[0]; // Output: Apple
echo $fruits[1]; // Output: Banana
echo $fruits[2]; // Output: Cherry

// Adding values
$fruits[] = "Date"; // Adds "Date" at the end of the array

// Looping through the array
foreach($fruits as $fruit) {
    echo $fruit . " ";
}
// Output: Apple Banana Cherry Date
?>

Associative Arrays

Associative arrays use named keys to access their values.

<?php
$ages = array("Peter" => 35, "Ben" => 37, "Joe" => 43);

// Accessing values
echo $ages["Peter"]; // Output: 35
echo $ages["Ben"]; // Output: 37
echo $ages["Joe"]; // Output: 43

// Adding values
$ages["Anna"] = 25; // Adds "Anna" => 25 to the array

// Looping through the array
foreach($ages as $name => $age) {
    echo "$name is $age years old. ";
}
// Output: Peter is 35 years old. Ben is 37 years old. Joe is 43 years old. Anna is 25 years old.
?>

Multidimensional Arrays

Multidimensional arrays contain one or more arrays within them.

<?php
$students = array(
    "John" => array("Math" => 85, "Science" => 78, "English" => 90),
    "Jane" => array("Math" => 92, "Science" => 88, "English" => 84),
    "Doe" => array("Math" => 70, "Science" => 75, "English" => 80)
);

// Accessing values
echo $students["John"]["Math"]; // Output: 85
echo $students["Jane"]["Science"]; // Output: 88
echo $students["Doe"]["English"]; // Output: 80

// Looping through the array
foreach($students as $name => $subjects) {
    echo "$name's scores: ";
    foreach($subjects as $subject => $score) {
        echo "$subject: $score ";
    }
    echo "\n";
}
// Output:
// John's scores: Math: 85 Science: 78 English: 90 
// Jane's scores: Math: 92 Science: 88 English: 84 
// Doe's scores: Math: 70 Science: 75 English: 80 
?>

Functions for Arrays

PHP provides a wide range of functions to manipulate arrays. Here are a few commonly used ones:

• count($array): Returns the number of elements in an array.
• array_merge($array1, $array2): Merges two or more arrays.
• array_keys($array): Returns all the keys of an array.
• array_values($array): Returns all the values of an array.
• in_array($value, $array): Checks if a value exists in an array.

Example

<?php
$colors = array("Red", "Green", "Blue");

// Count elements
echo count($colors); // Output: 3

// Merge arrays
$moreColors = array("Yellow", "Purple");
$allColors = array_merge($colors, $moreColors);

// Print merged array
foreach($allColors as $color) {
    echo $color . " ";
}
// Output: Red Green Blue Yellow Purple

// Check if a value exists
if(in_array("Green", $allColors)) {
    echo "Green is in the array.";
} else {
    echo "Green is not in the array.";
}
// Output: Green is in the array.
?>

These examples cover the basics of PHP arrays. They are fundamental for managing and manipulating collections of data in PHP.