PHP Arrays & Iteration Patterns

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Last updated: September 2026 84 Verified Examples
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How to create Multidimensional Associative Array in PHP?

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Constructs nested associative arrays with key-value pairs.

Program (PHP)
<?php

$employees = [
    "EMP101" => [
        "name" => "John Doe",
        "department" => "Engineering",
        "skills" => ["PHP", "Laravel", "MySQL"]
    ],
    "EMP102" => [
        "name" => "Jane Smith",
        "department" => "Design",
        "skills" => ["UI/UX", "Figma", "CSS"]
    ]
];

echo "Employee EMP101 Name: " . $employees["EMP101"]["name"] . "\n";
echo "Skills: " . implode(", ", $employees["EMP101"]["skills"]) . "\n";
?>
Expected Output
Employee EMP101 Name: John Doe
Skills: PHP, Laravel, MySQL

PHP Indexed and Associative Arrays

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Shows how to define and access indexed and key-value associative arrays.

Program (PHP)
<?php

// Indexed Array
$colors = ["Red", "Green", "Blue"];
echo "First color: " . $colors[0] . "\n";

// Associative Array
$user = [
    "name" => "Sarah",
    "role" => "Developer"
];
echo "User Name: " . $user["name"] . ", Role: " . $user["role"] . "\n";
?>
Expected Output
First color: Red
User Name: Sarah, Role: Developer

How to insert a new item in an array on any position in PHP?

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Inserts an element at a specific index in a PHP array using array_splice().

Program (PHP)
<?php

$array = ['Apple', 'Banana', 'Date'];
$newItem = 'Cherry';
$position = 2;

array_splice($array, $position, 0, $newItem);

print_r($array);
?>
Expected Output
Array
(
    [0] => Apple
    [1] => Banana
    [2] => Cherry
    [3] => Date
)

How to append one array to another in PHP?

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Combines and appends elements of one array to another using array_merge().

Program (PHP)
<?php

$array1 = ['PHP', 'Python'];
$array2 = ['JavaScript', 'C++'];

$result = array_merge($array1, $array2);

print_r($result);
?>
Expected Output
Array
(
    [0] => PHP
    [1] => Python
    [2] => JavaScript
    [3] => C++
)

How to delete an Element From an Array in PHP?

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Removes an element at a specific index using unset().

Program (PHP)
<?php

$fruits = ['Apple', 'Banana', 'Cherry', 'Date'];

// Delete element at index 1 ('Banana')
unset($fruits[1]);

print_r($fruits);
?>
Expected Output
Array
(
    [0] => Apple
    [2] => Cherry
    [3] => Date
)

How to print all the values of an array in PHP?

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Iterates and prints all array elements using a foreach loop and implode().

Program (PHP)
<?php

$languages = ['PHP', 'JavaScript', 'Python', 'Java'];

echo "Using foreach:\n";
foreach ($languages as $lang) {
    echo "- $lang\n";
}

echo "\nJoined String: " . implode(', ', $languages) . "\n";
?>
Expected Output
Using foreach:
- PHP
- JavaScript
- Python
- Java

Joined String: PHP, JavaScript, Python, Java

How to perform Array Delete by Value Not Key in PHP?

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Locates an element value using array_search() and removes it using unset().

Program (PHP)
<?php

$colors = ['red', 'green', 'blue', 'yellow'];
$valueToRemove = 'blue';

if (($key = array_search($valueToRemove, $colors)) !== false) {
    unset($colors[$key]);
}

print_r($colors);
?>
Expected Output
Array
(
    [0] => red
    [1] => green
    [3] => yellow
)

How to remove Array Element and do Re-Indexing in PHP?

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Removes an array element and resets array keys using array_values().

Program (PHP)
<?php

$numbers = [10, 20, 30, 40, 50];

// Delete index 2 (30)
unset($numbers[2]);

// Re-index numerical array keys
$reindexed = array_values($numbers);

print_r($reindexed);
?>
Expected Output
Array
(
    [0] => 10
    [1] => 20
    [2] => 40
    [3] => 50
)

How to count all array elements in PHP?

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Calculates the total number of elements in an array using count().

Program (PHP)
<?php

$items = ['PHP', 'Laravel', 'MySQL', 'Vue.js'];

echo "Total Elements: " . count($items) . "\n";
?>
Expected Output
Total Elements: 4

How to insert an item at the beginning of an array in PHP?

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Prepends one or more items to the start of an array using array_unshift().

Program (PHP)
<?php

$stack = ['Python', 'Java'];

array_unshift($stack, 'PHP', 'C++');

print_r($stack);
?>
Expected Output
Array
(
    [0] => PHP
    [1] => C++
    [2] => Python
    [3] => Java
)

How to check if two arrays contain the same elements?

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Compares two arrays regardless of order using array_diff() and count().

Program (PHP)
<?php

$arr1 = [1, 2, 3, 4];
$arr2 = [4, 3, 2, 1];

$areEqual = (count($arr1) === count($arr2)) && empty(array_diff($arr1, $arr2)) && empty(array_diff($arr2, $arr1));

if ($areEqual) {
    echo "Both arrays contain the exact same elements.\n";
} else {
    echo "Arrays differ.\n";
}
?>
Expected Output
Both arrays contain the exact same elements.

How to merge two arrays keeping original keys in PHP?

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Merges arrays while preserving original keys using array_replace() or the union (+) operator.

Program (PHP)
<?php

$array1 = [10 => 'a', 20 => 'b'];
$array2 = [30 => 'c', 40 => 'd'];

$merged = $array1 + $array2;

print_r($merged);
?>
Expected Output
Array
(
    [10] => a
    [20] => b
    [30] => c
    [40] => d
)

How to find the maximum and the minimum in a PHP array?

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Finds highest and lowest numerical values in an array using max() and min().

Program (PHP)
<?php

$numbers = [42, 17, 89, 5, 64, 23];

$maxVal = max($numbers);
$minVal = min($numbers);

echo "Maximum Value: $maxVal\n";
echo "Minimum Value: $minVal\n";
?>
Expected Output
Maximum Value: 89
Minimum Value: 5

How to check a key exists in an array in PHP?

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Determines if a specific key exists in an associative array using array_key_exists().

Program (PHP)
<?php

$user = [
    'id' => 101,
    'username' => 'alex_dev',
    'email' => 'alex@example.com'
];

if (array_key_exists('username', $user)) {
    echo "Key 'username' exists with value: " . $user['username'] . "\n";
}

if (!array_key_exists('phone', $user)) {
    echo "Key 'phone' does not exist.\n";
}
?>
Expected Output
Key 'username' exists with value: alex_dev
Key 'phone' does not exist.

How to find the second most frequent element in a PHP array?

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Counts element occurrences with array_count_values(), sorts descending, and retrieves 2nd item.

Program (PHP)
<?php

$arr = ['apple', 'banana', 'apple', 'cherry', 'apple', 'banana', 'banana', 'banana', 'cherry'];

$counts = array_count_values($arr);
arsort($counts);

$keys = array_keys($counts);
$secondMostFrequent = $keys[1] ?? null;

echo "Frequencies:\n";
print_r($counts);
echo "Second Most Frequent Element: " . $secondMostFrequent . "\n";
?>
Expected Output
Frequencies:
Array
(
    [banana] => 4
    [apple] => 3
    [cherry] => 2
)
Second Most Frequent Element: apple

How to sort an array of objects by object fields in PHP?

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Sorts array of objects by property value using usort() and spaceship operator.

Program (PHP)
<?php

class Person {
    public $name;
    public $age;
    public function __construct($name, $age) {
        $this->name = $name;
        $this->age = $age;
    }
}

$people = [
    new Person("Charlie", 35),
    new Person("Alice", 25),
    new Person("Bob", 30)
];

usort($people, function($a, $b) {
    return $a->age <=> $b->age;
});

foreach ($people as $p) {
    echo "Name: {$p->name}, Age: {$p->age}\n";
}
?>
Expected Output
Name: Alice, Age: 25
Name: Bob, Age: 30
Name: Charlie, Age: 35

How to print the last value of an array without affecting the pointer?

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Retrieves last element using array_key_last() without modifying internal array pointer.

Program (PHP)
<?php

$array = ['first', 'second', 'third', 'last'];

$lastKey = array_key_last($array);
$lastValue = $array[$lastKey];

echo "Last Element: " . $lastValue . "\n";
echo "Current Pointer Value: " . current($array) . "\n";
?>
Expected Output
Last Element: last
Current Pointer Value: first

How to merge the first index of an array with the first index of the second array?

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Extracts the initial elements of two arrays and merges them into a new array.

Program (PHP)
<?php

$arr1 = ['Apple', 'Banana', 'Cherry'];
$arr2 = ['Red', 'Yellow', 'Dark Red'];

$mergedFirst = [$arr1[0], $arr2[0]];

print_r($mergedFirst);
?>
Expected Output
Array
(
    [0] => Apple
    [1] => Red
)

How to sort an Array of Associative Arrays by Value of a Given Key in PHP?

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Sorts array of associative arrays by specific key using usort() and spaceship operator.

Program (PHP)
<?php

$products = [
    ['name' => 'Laptop', 'price' => 1200],
    ['name' => 'Mouse', 'price' => 25],
    ['name' => 'Keyboard', 'price' => 75]
];

usort($products, function($a, $b) {
    return $a['price'] <=> $b['price'];
});

print_r($products);
?>
Expected Output
Array
(
    [0] => Array
        (
            [name] => Mouse
            [price] => 25
        )

    [1] => Array
        (
            [name] => Keyboard
            [price] => 75
        )

    [2] => Array
        (
            [name] => Laptop
            [price] => 1200
        )

)

How to make a leaderboard using PHP?

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Builds a score-based leaderboard by sorting associative array descending.

Program (PHP)
<?php

$players = [
    ['name' => 'Alice', 'score' => 450],
    ['name' => 'Bob', 'score' => 780],
    ['name' => 'Charlie', 'score' => 620],
    ['name' => 'Diana', 'score' => 910]
];

usort($players, function($a, $b) {
    return $b['score'] <=> $a['score'];
});

echo "--- GAME LEADERBOARD ---\n";
foreach ($players as $rank => $player) {
    $position = $rank + 1;
    echo "#{$position} {$player['name']} - {$player['score']} pts\n";
}
?>
Expected Output
--- GAME LEADERBOARD ---
#1 Diana - 910 pts
#2 Bob - 780 pts
#3 Charlie - 620 pts
#4 Alice - 450 pts

How to check an array is multidimensional or not in PHP?

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Checks whether an array contains nested child arrays using is_array().

Program (PHP)
<?php

function isMultidimensional(array $arr): bool {
    foreach ($arr as $element) {
        if (is_array($element)) {
            return true;
        }
    }
    return false;
}

$singleArr = [1, 2, 3];
$multiArr = [1, [2, 3], 4];

echo "singleArr is multi: " . (isMultidimensional($singleArr) ? "Yes" : "No") . "\n";
echo "multiArr is multi: " . (isMultidimensional($multiArr) ? "Yes" : "No") . "\n";
?>
Expected Output
singleArr is multi: No
multiArr is multi: Yes

How to merge the duplicate value in multidimensional array in PHP?

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Groups entries by category key to merge duplicate data values.

Program (PHP)
<?php

$data = [
    ['category' => 'Fruit', 'item' => 'Apple'],
    ['category' => 'Fruit', 'item' => 'Banana'],
    ['category' => 'Vegetable', 'item' => 'Carrot'],
    ['category' => 'Fruit', 'item' => 'Orange']
];

$merged = [];
foreach ($data as $entry) {
    $cat = $entry['category'];
    if (!isset($merged[$cat])) {
        $merged[$cat] = [];
    }
    $merged[$cat][] = $entry['item'];
}

print_r($merged);
?>
Expected Output
Array
(
    [Fruit] => Array
        (
            [0] => Apple
            [1] => Banana
            [2] => Orange
        )

    [Vegetable] => Array
        (
            [0] => Carrot
        )

)

How to convert multidimensional array to XML file in PHP?

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Recursively converts nested arrays into an XML string using SimpleXMLElement.

Program (PHP)
<?php

function arrayToXml($data, &$xmlData) {
    foreach ($data as $key => $value) {
        if (is_numeric($key)) {
            $key = 'item' . $key;
        }
        if (is_array($value)) {
            $subnode = $xmlData->addChild($key);
            arrayToXml($value, $subnode);
        } else {
            $xmlData->addChild("$key", htmlspecialchars("$value"));
        }
    }
}

$data = [
    'user' => [
        'name' => 'Alice',
        'role' => 'Developer',
        'languages' => ['PHP', 'JavaScript']
    ]
];

$xml = new SimpleXMLElement('<root/>');
arrayToXml($data, $xml);

echo $xml->asXML();
?>
Expected Output
<?xml version="1.0"?>
<root><user><name>Alice</name><role>Developer</role><languages><item0>PHP</item0><item1>JavaScript</item1></languages></user></root>

How to search by multiple key => value in PHP array?

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Filters array items against multiple criteria using array_filter().

Program (PHP)
<?php

$users = [
    ['id' => 1, 'role' => 'admin', 'status' => 'active'],
    ['id' => 2, 'role' => 'editor', 'status' => 'active'],
    ['id' => 3, 'role' => 'admin', 'status' => 'inactive'],
    ['id' => 4, 'role' => 'admin', 'status' => 'active']
];

$searchCriteria = ['role' => 'admin', 'status' => 'active'];

$filtered = array_filter($users, function($user) use ($searchCriteria) {
    foreach ($searchCriteria as $key => $val) {
        if (!isset($user[$key]) || $user[$key] !== $val) {
            return false;
        }
    }
    return true;
});

print_r(array_values($filtered));
?>
Expected Output
Array
(
    [0] => Array
        (
            [id] => 1
            [role] => admin
            [status] => active
        )

    [1] => Array
        (
            [id] => 4
            [role] => admin
            [status] => active
        )

)

How to search by key=>value in a multidimensional array in PHP?

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Locates array index matching specific key-value using array_column() and array_search().

Program (PHP)
<?php

$products = [
    ['id' => 101, 'name' => 'Laptop', 'category' => 'Electronics'],
    ['id' => 102, 'name' => 'Desk Chair', 'category' => 'Furniture'],
    ['id' => 103, 'name' => 'Smartphone', 'category' => 'Electronics']
];

$keyIndex = array_search('Desk Chair', array_column($products, 'name'));

if ($keyIndex !== false) {
    echo "Found product:\n";
    print_r($products[$keyIndex]);
}
?>
Expected Output
Found product:
Array
(
    [id] => 102
    [name] => Desk Chair
    [category] => Furniture
)

How to merge two or more arrays using array_merge()?

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Combines multiple indexed and associative arrays using array_merge().

Program (PHP)
<?php

$frontend = ['HTML', 'CSS', 'JavaScript'];
$backend = ['PHP', 'Python', 'Node.js'];
$database = ['MySQL', 'PostgreSQL'];

$fullStack = array_merge($frontend, $backend, $database);

print_r($fullStack);
?>
Expected Output
Array
(
    [0] => HTML
    [1] => CSS
    [2] => JavaScript
    [3] => PHP
    [4] => Python
    [5] => Node.js
    [6] => MySQL
    [7] => PostgreSQL
)

How to count rows in MySQL table in PHP?

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Demonstrates SQL COUNT(*) query pattern using PDO fetchColumn().

Program (PHP)
<?php

$sql = "SELECT COUNT(*) FROM orders WHERE status = 'completed'";

echo "SQL Query: $sql\n";
echo "Execution Pattern: \$count = \$pdo->query(\$sql)->fetchColumn();\n";
?>
Expected Output
SQL Query: SELECT COUNT(*) FROM orders WHERE status = 'completed'
Execution Pattern: $count = $pdo->query($sql)->fetchColumn();

PHP Core Concepts & Feature Breakdown

DomainCore ConceptsPrimary Use CaseOfficial Docs
Variables & Types$var, string, int, boolVariables, string concatenation, type declarationsPHP Types
Arrays & DataIndexed arrays, Associative ['key' => 'val']Key-value mappings, list iteration with foreachPHP Arrays
Functionsfunction name(type $param): returnTypeModular code, default arguments, return value typingPHP Functions
OOP Constructsclass, extends, public/protectedEncapsulation, constructors, inheritance, web frameworksPHP OOP

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Frequently Asked Questions

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Yes. All programs utilize modern PHP standard syntax, typed properties/arguments, short array syntax [], and standard OOP paradigms compatible with PHP 7.4 through PHP 8.x and frameworks such as Laravel and Symfony.

Absolutely. These examples cover essential backend concepts frequently requested during technical evaluations: string operations, prime checks, Fibonacci algorithms, associative array iteration, JSON parsing, and object-oriented inheritance.

Learn PHP by Practicing Examples

PHP powers over 75% of the active web today. Practicing short, clear programs is the most efficient path to mastering PHP backend development. Each snippet focuses on a fundamental building block — from basic variable output and control structures to complex associative arrays, JSON serialization, and object-oriented design.

Beginner Foundations

Learn echo syntax, variable assignment, type coercion, and simple arithmetic operations.

Arrays & Logic

Master key-value arrays, foreach loops, function type hints, and string/math helpers.

OOP & Files

Explore classes, inheritance, visibility, JSON APIs, and file read/write operations.