Yield keyword behavior in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the yield keyword do in PHP?

The yield keyword allows a function to return a value to the caller without losing its state, enabling the function to be resumed later to produce a sequence of values one at a time.

beginner

How is yield different from return in PHP?

return ends the function and sends a single value back, while yield pauses the function, sends a value back, and allows the function to continue from where it left off when called again.

intermediate

What type of object does a function using yield return in PHP?

It returns a Generator object, which can be iterated over to get each yielded value one by one.

intermediate

Can yield send keys along with values? How?

Yes, you can use yield key => value; to send both a key and a value, which is useful when iterating over the generator with keys.

intermediate

Why use yield instead of building an array in PHP?

Using yield saves memory because it generates values one at a time instead of creating a full array in memory, which is helpful for large data sets or infinite sequences.

What does the yield keyword return when used inside a PHP function?

A A Generator object

B An array

C A string

D A boolean

yield returns a Generator object that can be iterated to get each yielded value.

Which statement about yield is true?

A <code>yield</code> pauses the function and returns a value

B <code>yield</code> immediately ends the function

C <code>yield</code> returns all values at once

D <code>yield</code> is used to declare variables

yield pauses the function and returns a value, allowing the function to resume later.

How do you send a key and value using yield?

A yield value => key;

B yield (key, value);

C yield key => value;

D yield key, value;

The syntax yield key => value; sends both a key and a value.

Why might you prefer yield over returning an array?

A It converts values to strings

B It runs faster because it returns all values immediately

C It automatically sorts the values

D It uses less memory by generating values one at a time

yield generates values one at a time, saving memory compared to building a full array.

What happens if you call a function with yield multiple times?

A It returns the last yielded value only

B It produces a sequence of values, one per call to the generator

C It throws an error

D It returns an array of all yielded values

Each call to the generator's next() method resumes the function and produces the next yielded value.

Explain how the yield keyword works in PHP and how it differs from return.

Think about how <code>yield</code> lets a function produce multiple values over time.

Describe a situation where using yield is better than returning an array.

Consider when you have many values but don't want to store them all at once.