[Helppp xD] Newbie issue

Ruby
1

Hi all!!

I’ve declared a method inside the string class that has to answer the
amount of “X” and “2” chars in a string. The string is ALWAYS gonna be
15 chars size. The code is the following:

class String

    # DAME VARIANTES
def variantes
	@variantes = 0
	15.times do |@cont|
		if (self[@cont] == "2" || self[@cont] == "X")
			@variantes = @variantes + 1
		end
	end

	return @variantes
end

end

cadena = “XX222XX222XX1X2”
puts cadena.variantes

And the last line ALWAYS ANSWERS a CERO. Why? Why it doesn’t enter the
if statement inside the method?

Thx

2

Flaab M. wrote:

  @variantes = 0

cadena = “XX222XX222XX1X2”
puts cadena.variantes

And the last line ALWAYS ANSWERS a CERO. Why? Why it doesn’t enter the
if statement inside the method?

Thx

String#[] returns the integer code of the character at that position.

So, either use

if(self[@cont] == ?2 || self[@cont] == ?X)

or
if(self[@cont…@cont] == “2” || self[@cont…@cont] == “X”)

Also:

  1. You shouldn’t use instance variables when local ones will suffice.
    I.e. use “variantes” and “cont” instead of “@variantes” and “@cont”

  2. Please send code snippets with identifiers in English - it takes a
    little guesswork out of what you’re trying to achieve.

  3. Smileys and netspeak are fluff and a little out of place for the
    medium. Cut out the “xD” and use “Thanks” instead of Thx, please.

David V.

3

Check the manual

str[0] will return a numeric representation of the character
what You need is str[0,1] one character starting from the first
position.

Try this:

class String
def variantes
@variantes = 0
Range.new(0, 14).each { |i|
if (self[i,1] == “2” || self[i,1] == “X”)
@variantes = @variantes + 1
end
}
return @variantes
end
end

str = “XXXXX22222XXXXX”
puts str.variantes

Dmitry

4

Now that you got a couple answers why your comparisons didn’t work,
time to suggest a better method.

class String
def variantes
count “2X”
end
end

5

Matthew M. wrote:

Now that you got a couple answers why your comparisons didn’t work,
time to suggest a better method.

class String
def variantes
count “2X”
end
end

Wow THANKS i´m amazed… =D That’s pretty better!

I’m newbie at ruby didn’t know it had such a simple way to do this.

Thanks a lot

6

Hi –

On Fri, 17 Nov 2006, David V. wrote:

  1. Smileys and netspeak are fluff and a little out of place for the
    medium. Cut out the “xD” and use “Thanks” instead of Thx, please.

Oh, I think we do OK despite the occasional smiley :slight_smile: Let’s err on
the side of making people feel welcome unless they do something
clearly troll-like.

Thx –

David