Ruby Language Catching Exceptions with Begin / Rescue Checking Whether No Error Was Raised
Example
You can use an else clause for code that will be run if no error is raised.
def divide(x, y)
begin
z = x/y
rescue ZeroDivisionError
puts "Don't divide by zero!"
rescue TypeError
puts "Division only works on numbers!"
return nil
rescue => e
puts "Don't do that (%s)" % [e.class]
return nil
else
puts "This code will run if there is no error."
return z
end
end
The else clause does not run if there is an error that transfers control to one of the rescue clauses:
> divide(10,0)
Don't divide by zero!
=> nil
But if no error is raised, the else clause executes:
> divide(10,2)
This code will run if there is no error.
=> 5
Note that the else clause will not be executed if you return from the begin clause
def divide(x, y)
begin
z = x/y
return z # Will keep the else clause from running!
rescue ZeroDivisionError
puts "Don't divide by zero!"
else
puts "This code will run if there is no error."
return z
end
end
> divide(10,2)
=> 5
