String freezing for immutability in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does freezing a string in Ruby do?

Freezing a string makes it immutable, meaning you cannot change its content after freezing.

beginner

How do you freeze a string in Ruby?

You call the freeze method on the string, like str.freeze.

intermediate

What happens if you try to modify a frozen string in Ruby?

Ruby raises a FrozenError because the string cannot be changed once frozen.

intermediate

Why might you want to freeze strings in Ruby?

Freezing strings can improve performance by avoiding duplicate string objects and prevent accidental changes.

beginner

What is the difference between a frozen string and a regular string in Ruby?

A frozen string cannot be changed after creation, while a regular string can be modified anytime.

How do you make a string immutable in Ruby?

A Call <code>freeze</code> on the string

B Use <code>immutable()</code> method

C Declare string as <code>const</code>

D Use <code>lock()</code> method

In Ruby, calling freeze on a string makes it immutable.

What error is raised when modifying a frozen string?

A TypeError

B NoMethodError

C RuntimeError

D FrozenError

Trying to modify a frozen string raises a FrozenError in Ruby.

Which of these is a benefit of freezing strings?

A Allows string to be changed faster

B Prevents accidental modification

C Makes string longer

D Automatically encrypts string

Freezing strings prevents accidental changes and can improve performance.

What does this code do? str = "hello".freeze

A Creates a mutable string

B Deletes the string

C Creates an immutable string

D Copies the string

The string "hello" is frozen and cannot be changed after this.

Can you unfreeze a string once it is frozen?

A No, freezing is permanent

B Yes, by reassigning

C Yes, with <code>thaw</code>

D Yes, with <code>unfreeze</code>

Once a string is frozen in Ruby, it cannot be unfrozen or changed.

Explain what string freezing means in Ruby and why it is useful.

Think about how freezing stops changes and why that might help.

Describe what happens if you try to change a frozen string in Ruby.

What kind of error does Ruby give when you break the rule?