Yield keyword behavior in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to yield values from the generator function.

PHP

<?php
function numbers() {
    yield [1];
}

foreach (numbers() as $num) {
    echo $num . " ";
}
?>

Drag options to blanks, or click blank then click option'

A1

Bprint 1

Creturn 1

Decho 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using echo or print instead of yield inside the generator.

Using return instead of yield which ends the function.

The yield keyword outputs a value from the generator. Here, yield 1; yields the value 1.

2fill in blank

medium

Complete the code to yield keys and values from the generator.

PHP

<?php
function letters() {
    yield [1] => 'a';
    yield 'b';
}

foreach (letters() as $key => $value) {
    echo "$key:$value ";
}
?>

Drag options to blanks, or click blank then click option'

A'first'

B0

C1

D'a'

Attempts:

3 left

💡 Hint

Common Mistakes

Using a number key when a string key is expected.

Omitting the key and only yielding values.

To yield a key and value, use yield 'key' => 'value';. Here, the key is 'first'.

3fill in blank

hard

Fix the error in the generator function to yield numbers 1 to 3.

PHP

<?php
function countToThree() {
    for ($i = 1; $i <= 3; $i++) {
        [1] $i;
    }
}

foreach (countToThree() as $num) {
    echo $num . " ";
}
?>

Drag options to blanks, or click blank then click option'

Areturn

Bprint

Cecho

Dyield

Attempts:

3 left

💡 Hint

Common Mistakes

Using return inside the loop which stops the generator after first value.

Using echo or print which outputs but does not yield values.

Inside a generator, use yield to output each value. Using return would end the function immediately.

4fill in blank

hard

Fill both blanks to create a generator that yields squares of numbers greater than 2.

PHP

<?php
function squares($numbers) {
    foreach ($numbers as $n) {
        if ($n [1] 2) {
            yield $n[2]2;
        }
    }
}

foreach (squares([1, 2, 3, 4]) as $square) {
    echo $square . " ";
}
?>

Drag options to blanks, or click blank then click option'

A**

B>

C<

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using * instead of ** for exponentiation.

Using < instead of > in the condition.

In the generator function, use > to check if $n > 2 and ** to compute the square $n ** 2, then yield it. This yields 9 and 16.

5fill in blank

hard

Fill all three blanks to yield keys as uppercase and values as their length for words longer than 3 letters.

PHP

<?php
function wordInfo($words) {
    foreach ($words as $word) {
        if (strlen($word) [1] 3) {
            yield [2] => [3];
        }
    }
}

foreach (wordInfo(['apple', 'bat', 'carrot']) as $key => $value) {
    echo "$key:$value ";
}
?>

Drag options to blanks, or click blank then click option'

A>

Bstrlen($word)

C$word

Dstrtoupper($word)

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of > in the condition.

Yielding the word as key without converting to uppercase.

Yielding the word instead of its length as value.

The condition checks if the word length is greater than 3. The key is the uppercase word, and the value is its length.