Ruby Language Catching Exceptions with Begin / Rescue Checking for Different Errors
Example
If you want to do different things based on the kind of error, use multiple rescue clauses, each with a different error type as an argument.
def divide(x, y)
begin
return x/y
rescue ZeroDivisionError
puts "Don't divide by zero!"
return nil
rescue TypeError
puts "Division only works on numbers!"
return nil
end
end
> divide(10, 0)
Don't divide by zero!
> divide(10, 'a')
Division only works on numbers!
If you want to save the error for use in the rescue block:
rescue ZeroDivisionError => e
Use a rescue clause with no argument to catch errors of a type not specified in another rescue clause.
def divide(x, y)
begin
return x/y
rescue ZeroDivisionError
puts "Don't divide by zero!"
return nil
rescue TypeError
puts "Division only works on numbers!"
return nil
rescue => e
puts "Don't do that (%s)" % [e.class]
return nil
end
end
> divide(nil, 2)
Don't do that (NoMethodError)
In this case, trying to divide nil by 2 is not a ZeroDivisionError or a TypeError, so it handled by the default rescue clause, which prints out a message to let us know that it was a NoMethodError.
