Multiple rescue clauses in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of multiple rescue clauses in Ruby?

Multiple rescue clauses allow you to handle different types of errors separately, giving specific responses for each error type.

beginner

How do you write multiple rescue clauses in Ruby?

You write multiple rescue clauses by listing different rescue blocks one after another, each specifying a different error class to catch.

intermediate

What happens if an exception does not match any rescue clause?

If an exception does not match any rescue clause, it will propagate up the call stack and may cause the program to terminate if not handled elsewhere.

beginner

Example: What will this code output?

begin
  1 / 0
rescue ZeroDivisionError
  puts 'Cannot divide by zero'
rescue StandardError
  puts 'Some other error'
end

The output will be: Cannot divide by zero Because the error is ZeroDivisionError, the first rescue clause handles it.

intermediate

Can you rescue multiple exceptions in a single rescue clause?

Yes, you can rescue multiple exceptions by listing them separated by commas after rescue, like: rescue IOError, EOFError.

What keyword is used to handle exceptions in Ruby?

A try

B catch

C rescue

D except

In Ruby, the keyword 'rescue' is used to handle exceptions.

If you want to handle both IOError and EOFError in the same rescue clause, how do you write it?

A rescue IOError | EOFError

B rescue IOError, EOFError

C rescue (IOError, EOFError)

D rescue IOError && EOFError

You list multiple exceptions separated by commas after rescue: rescue IOError, EOFError.

What happens if an exception is not rescued in any rescue clause?

A The program crashes or the exception propagates up

B The exception is ignored silently

C The program restarts automatically

D The exception is converted to a warning

If an exception is not rescued, it propagates up and may crash the program.

Which rescue clause will handle a ZeroDivisionError if multiple rescue clauses exist?

A The first rescue clause that matches ZeroDivisionError

B The last rescue clause

C All rescue clauses

D None, ZeroDivisionError is not rescued

Ruby executes the first rescue clause that matches the exception type.

Can you have an else clause after multiple rescue clauses?

A No, else is not allowed

B Only if you have a finally clause

C Yes, but it runs only if an exception occurs

D Yes, it runs if no exception occurs

The else clause runs only if no exceptions are raised in the begin block.

Explain how multiple rescue clauses work in Ruby and why they are useful.

Think about catching different problems separately.

Write a Ruby code snippet that rescues both ZeroDivisionError and TypeError with different messages.

Use separate rescue clauses for each error.