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Ruby Ruby Loops Ruby Loops Loop Conditionals

Posted by sebastien penot
sebastien penot
3,292 Points

Why do you need to declare the empty string "name" at the beginning of the function?

In the video tutorial, Jason declares an empty String name at the beginning of the function. Why is this required? I just returned the variable answer before breaking the loop and the method worked. 

def get_name 
puts " Please enter your name (it must contain at least 5 characters): "  
  loop do
  answer = gets.chomp
    if answer.length >= 5
    puts "Hi #{answer}, nice to meet you"
      return answer
      break
    else
    puts "Your name requires at least 5 characters, please try again"
    end
  end  
end

2 Answers

Meagan Waller
Meagan Waller
19,382 Points
Meagan Waller
Meagan Waller
19,382 Points

Hi Sebastien,

The reason that name is set to an empty string before the loop is due to scoping.

If you were to run this code without declaring name outside of the loop you'd get this error:

NameError: undefined local variable or method 'name' for main:Object

The reason for that is because variables declared inside of a loop are available to that loop only. So, if name was only declared inside the loop as name = gets.chomp, that name variable and assignment is lost once you exit the loop, and the return name statement at the end of the function would not know what name means.

By declaring name as an empty string outside of the loop, the variable name is now available to the entire function. The loop inside of the function can modify it; and it does by reassigning the value from an empty string to gets.chomp.

Try running this code without declaring the name = "" before the loop and you'll see what I mean. Make sense?

Also, this blog post might be helpful to you!

William Li
William Li
Courses Plus Student 26,868 Points
William Li
William Li
Courses Plus Student 26,868 Points

Meagan, yeah, in Jason's version of the code during lecture, name has to be set to an empty string; but in the code posted here, Sebastien actually made a change by moving the return statement inside the loop, this new version can in fact works without first setting name as empty string outside of the loop. So yeah, both versions are correct.

Unsubscribed User
Unsubscribed User
11,042 Points

Thanks for the explanation! ...but I couldn' t get why it doesn't work in this way too - I've placed the name variable outside the method declaration, so I think that it would be visible even inside the method definition, but It throws this error: undefined local variable or method `name' for main:Object (NameError)

name = ''

def get_name
  loop do
    print 'Enter your name, minimum 2 chars and no numbers: '
    name = gets.chomp
    if name.length >= 2 && !name.index(/\d/)
      break
    else
      puts 'Name must be longer than 2 chars and not contain any numbers.'
    end
  end
  return name
end


name = get_name
puts "Hi #{name}"
William Li
PLUS
William Li
Courses Plus Student 26,868 Points
William Li
William Li
Courses Plus Student 26,868 Points

I just took a quick look at your code, it seems that you're right; there's no need to declare name as empty string here.