Foreach loop for arrays in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a foreach loop used for in PHP?

A foreach loop is used to easily go through each item in an array, one by one, without needing to know the array's size.

beginner

How do you write a basic foreach loop to print all values in an array named $fruits?

foreach ($fruits as $fruit) { echo $fruit; }

intermediate

What does this code do? <br> foreach ($colors as $key => $value) { echo "$key: $value"; }

It goes through the $colors array and prints each key and its matching value, like 'red: #ff0000'.

intermediate

Can you modify array values inside a foreach loop in PHP?

Yes, but you must use a reference by adding & before the value variable, like: foreach ($arr as &$value) { $value = $value * 2; }

beginner

What happens if you use foreach on an empty array?

The loop does not run at all because there are no items to go through.

Which keyword starts a foreach loop in PHP?

A for

B foreach

C while

D loop

The foreach keyword is used specifically to loop through arrays in PHP.

How do you access the key and value inside a foreach loop?

A foreach ($array as $key => $value)

B foreach ($array as $value => $key)

C foreach ($array as $value)

D foreach ($array as $key)

The correct syntax to get both key and value is foreach ($array as $key => $value).

What will this code output? <br> $nums = [1, 2, 3]; foreach ($nums as $n) { echo $n; }

A 123

B 1 2 3

C Array

D Error

The loop prints each number one after another without spaces, so output is '123'.

How do you change values inside a foreach loop?

A You cannot change values in foreach

B Use $GLOBALS

C Use & before the value variable

D Use a for loop instead

Adding & before the value variable lets you modify the original array values inside the loop.

What happens if the array is empty in a foreach loop?

A It runs infinitely

B It runs once with null

C It throws an error

D The loop does not run

If the array is empty, foreach simply skips the loop body.

Explain how a foreach loop works with arrays in PHP.

Think about how you would tell a friend to read each item in a list one by one.

Describe how to modify array values inside a foreach loop and why you need a reference.

Imagine you want to change the original list items, not just copies.