Is an elsif loop possible?

ruby-talk
1

Hi Everyone,

I don't know if this is possible as I haven't found anything on google
or in here. Is it possible to have an elsif to be looped?

$Str = gets.chomp
if $Str.to_i < 0
  puts 'Sorry you cannot be that weak. Please enter a valid stat.'
    elsif $Str.to_i > StartStats.to_i
      puts 'You cannot give more stats than what you have available.
Please enter a valid stat.'
        else puts 'Your Strength is '+($Str)
end

Is there a way to make this a loop so that if $Str.to_i < 0 it would
restart and ask for an input again? Even if the answer is the same it
would still restart?

I tried setting up a retry and redo but I couldn't get it to work.

Thank you for your time.

···

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2

What you want is an 'until' loop:
http://www.techotopia.com/index.php/Ruby_While_and_Until_Loops#unless_and_until

"until the input is correct, keep looping."

3

Thank you Steve. That was exactly what I needed.

This works perfectly.

$Str = gets.chomp
$Str.to_i < 0
  until $Str.to_i > 0
  puts 'Sorry you cannot be that weak. Please enter a valid stat.'
$Str = gets.chomp
end
$Str.to_i > StartStats.to_i
  until $Str.to_i < StartStats.to_i
  puts 'You cannot give more stats than what you have available. Please
enter a valid stat.'
$Str = gets.chomp
end

That site is an excellent resource.
Thanks again Steve.

···

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4

Devin Rawlek wrote in post #986991:

Thank you Steve. That was exactly what I needed.

This works perfectly.

$Str = gets.chomp
$Str.to_i < 0

What is that line for? As written it does nothing: the comparison
evaluates to either true or false and then the value is discarded.

  until $Str.to_i > 0

Note that any until loop can be written as a while loop:

while $Str.to_i <= 0

and while loops are much clearer in meaning.

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5

and while loops are much clearer in meaning.

That's a purely subjective point to make and, in my opinion, often untrue.

while !x.nil?
  // body
end

vs.

until x.nil?
  // body
end

is a simple example where I like the until version better. Once DeMorgan's
law kicks in for certain negations, until loops can become much cleaner. Example:

while !x.nil? || y < 0
  // body
end

until x.nil? && y >= 0
// body
end

I personally think the until loop there is *much* simpler to read.

Michael Edgar
adgar@carboni.ca
http://carboni.ca/

···

On Mar 11, 2011, at 5:57 PM, 7stud -- wrote:

Devin Rawlek wrote in post #986991:

Thank you Steve. That was exactly what I needed.

This works perfectly.

$Str = gets.chomp
$Str.to_i < 0

What is that line for? As written it does nothing: the comparison
evaluates to either true or false and then the value is discarded.

until $Str.to_i > 0

Note that any until loop can be written as a while loop:

while $Str.to_i <= 0

and while loops are much clearer in meaning.

--
Posted via http://www.ruby-forum.com/\.

6

Agreed, especially in this instance. You want to process until the input is
correct. 'while not' is just awkward.