Error Handling

In Ruby, error handling is typically done using begin, rescue, and ensure blocks.

begin
  # Code that might raise an exception
  result = 10 / 0
rescue ZeroDivisionError => e
  # Handle specific exception
  puts "Error: #{e.message}"
rescue StandardError => e
  # Handle other types of exceptions
  puts "An unexpected error occurred: #{e.message}"
ensure
  # Code that will be executed no matter what (optional)
  puts "This code always runs."
end

• The begin block contains the code that might raise an exception.
• The rescue block catches specific types of exceptions. In this case, ZeroDivisionError and StandardError are caught.
• The ensure block contains code that will be executed whether an exception occurs or not. It's optional and can be omitted if not needed.

Handling Multiple Exceptions

You can have multiple rescue blocks to handle different types of exceptions.

begin
  # Code that might raise an exception
  result = 10 / 0
rescue ZeroDivisionError => e
  puts "Error: Division by zero - #{e.message}"
rescue ArgumentError => e
  puts "Error: Invalid argument - #{e.message}"
rescue StandardError => e
  puts "An unexpected error occurred: #{e.message}"
end

Using else

The else block contains code that will be executed if no exception occurs in the begin block.

begin
  # Code that might raise an exception
  result = 10 / 2
rescue ZeroDivisionError => e
  puts "Error: Division by zero - #{e.message}"
else
  # Code to execute if no exception occurs
  puts "Result: #{result}"
end

Raising Exceptions

You can raise exceptions using the raise keyword, specifying the exception type and an optional error message.

def some_method(value)
  raise ArgumentError, "Invalid value" if value.nil?

  # Rest of the method code
end

Code Challenge

Write a Ruby function safe_divide that takes two parameters (numerator and denominator) and returns the result of the division. However, ensure that your function handles potential division by zero errors gracefully.