Foreach loop for arrays in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of foreach loop with associative array

What is the output of this PHP code?

PHP

<?php
$fruits = ['a' => 'Apple', 'b' => 'Banana', 'c' => 'Cherry'];
foreach ($fruits as $key => $value) {
    echo "$key:$value ";
}
?>

A a:Apple b:Banana c:Cherry

B 0:Apple 1:Banana 2:Cherry

C Apple Banana Cherry

D a b c

💡 Hint

Remember foreach can give both key and value when looping associative arrays.

The foreach loop iterates over each key-value pair. Using 'as $key => $value' prints the key and value separated by a colon.

❓ Predict Output

intermediate

Count iterations in foreach loop

What is the value of $count after this code runs?

PHP

<?php
$numbers = [10, 20, 30, 40];
$count = 0;
foreach ($numbers as $num) {
    $count++;
}
echo $count;
?>

A 3

B 4

C 0

D Error

💡 Hint

Count increases once per loop iteration.

The foreach loop runs once for each element in the array, so $count increments 4 times.

🔧 Debug

advanced

Identify error in foreach loop syntax

Which option shows the code that will cause a syntax error?

A <?php foreach ($arr as $value) { echo $value; } ?>

B <?php foreach ($arr as $value) echo $value; ?>

C <?php foreach $arr as $value { echo $value; } ?>

D <?php foreach ($arr as $key => $value) { echo $key; } ?>

💡 Hint

Check the parentheses and keywords in foreach syntax.

Option C misses parentheses around $arr and the 'foreach' keyword requires parentheses enclosing the array and variable.

❓ Predict Output

advanced

Output with nested foreach loops

What is the output of this PHP code?

PHP

<?php
$matrix = [[1,2],[3,4]];
foreach ($matrix as $row) {
    foreach ($row as $num) {
        echo $num;
    }
}
?>

A 1 2 3 4

B 1,2,3,4

C ArrayArray

D 1234

💡 Hint

Inner loop prints each number without spaces.

The nested loops print each number consecutively without spaces, resulting in '1234'.

🧠 Conceptual

expert

Behavior of foreach with reference variable

What will be the output of this PHP code?

PHP

<?php
$arr = [1, 2, 3];
foreach ($arr as &$value) {
    $value *= 2;
}
foreach ($arr as $value) {
    echo $value . ' ';
}
?>

A 2 4 4

B 2 4 6 3

C 2 4 6

D 1 2 3

💡 Hint

Remember that foreach by reference leaves the last reference variable linked.

The first loop doubles values by reference, making $arr=[2,4,6] and leaving $value as reference to $arr[2]. The second loop assigns to $value (modifying $arr[2]): 2 (sets to 2, echo 2), 4 (sets to 4, echo 4), 4 (echo 4).