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PHP Basic Code Challenges

 Here are some PHP code challenges ranging from beginner to intermediate levels:

  1. String Manipulation Challenge:

// Write a function that:

// - Takes a string

// - Removes all vowels

// - Returns the modified string

function removeVowels($str) {

    return preg_replace('/[aeiou]/i', '', $str);

}

// Test case

echo removeVowels("hello world"); // Output: "hll wrld"


  1. Array Manipulation Challenge:

// Write a function that:

// - Takes an array of numbers

// - Returns only the unique numbers

// - Preserves the original order

function getUniqueNumbers($arr) {

    return array_values(array_unique($arr));

}


// Test case

$numbers = [1, 2, 2, 3, 4, 4, 5];

print_r(getUniqueNumbers($numbers)); // Output: [1, 2, 3, 4, 5]

  1. Prime Number Checker:

function isPrime($num) {

    if ($num <= 1) return false;

    for ($i = 2; $i <= sqrt($num); $i++) {

        if ($num % $i == 0) return false;

    }

    return true;

}


// Test cases

echo isPrime(7);   // Output: true

echo isPrime(10);  // Output: false

  1. Reverse Words Challenge:

function reverseWords($sentence) {

    $words = explode(' ', $sentence);

    $reversedWords = array_map('strrev', $words);

    return implode(' ', $reversedWords);

}


// Test case

echo reverseWords("Hello World PHP"); 

// Output: "olleH dlroW PHP"

  1. Palindrome Checker:

function isPalindrome($str) {

    $cleanStr = strtolower(preg_replace('/[^a-z0-9]/', '', $str));

    return $cleanStr === strrev($cleanStr);

}


// Test cases

echo isPalindrome("A man, a plan, a canal: Panama"); // Output: true

echo isPalindrome("race a car"); // Output: false

  1. Fibonacci Sequence Generator:

function generateFibonacci($n) {

    $fibonacci = [0, 1];

    for ($i = 2; $i < $n; $i++) {

        $fibonacci[] = $fibonacci[$i-1] + $fibonacci[$i-2];

    }

    return $fibonacci;

}


// Test case

print_r(generateFibonacci(10)); 

// Output: Array of first 10 Fibonacci numbers

  1. Object-Oriented Challenge:

class ShoppingCart {

    private $items = [];


    public function addItem($name, $price) {

        $this->items[$name] = $price;

    }


    public function removeItem($name) {

        unset($this->items[$name]);

    }


    public function getTotalPrice() {

        return array_sum($this->items);

    }

}


// Test usage

$cart = new ShoppingCart();

$cart->addItem('Apple', 0.5);

$cart->addItem('Banana', 0.3);

echo $cart->getTotalPrice(); // Output: 0.8

  1. Regular Expression Challenge:

function validateEmail($email) {

    return preg_match('/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/', $email);

}


// Test cases

echo validateEmail("test@example.com");     // Output: 1 (true)

echo validateEmail("invalid-email");        // Output: 0 (false)

  1. Date Manipulation:

function daysBetweenDates($date1, $date2) {

    $datetime1 = new DateTime($date1);

    $datetime2 = new DateTime($date2);

    $interval = $datetime1->diff($datetime2);

    return $interval->days;

}


// Test case

echo daysBetweenDates('2023-01-01', '2023-12-31'); 

// Output: Number of days between dates

  1. Nested Array Flattening:

function flattenArray($arr) {

    $result = [];

    array_walk_recursive($arr, function($a) use (&$result) { $result[] = $a; });

    return $result;

}


// Test case

$nestedArray = [1, [2, 3], [4, [5, 6]]];

print_r(flattenArray($nestedArray)); 

// Output: [1, 2, 3, 4, 5, 6]


Bonus Challenge Levels:

  • Beginner: Solve the function

  • Intermediate: Add error handling

  • Advanced: Optimize for performance

Recommended Learning Path:

  1. Understand the problem

  2. Write a basic solution

  3. Test with different inputs

  4. Add error handling

  5. Optimize if possible

Tips:

  • Use var_dump() or print_r() for debugging

  • Write unit tests

  • Consider edge cases

  • Practice regularly
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