Discussion in 'Ruby' started by Kain Nobel, Jul 16, 2008.

1. Kain NobelGuest

Okay, so I wrote a script that'll allow the game player to jump with the
touch of a button. This script, I wanted a method that'll adjust the
distance in which
the game player jumps, based on the farthest passible tile. To define
the method, I used a 'for i' statement with 0 to the max distance, for
each passible 'space' he can jump, I push the value into an array named
'@spaces', respectively.

Code (Text):
def jump_dist
@spaces = []
case @direction
when 2 # Down
for i in 0...Jump::Distance
if passable?(self.x, self.y + i, 2)
@spaces[i] = i
return @spaces if i == Jump::Distance
end
end
when 4 # Left
for i in 0...Jump::Distance
if passable?(self.x - i, self.y, 4)
@spaces[i] = i
return @spaces if i == Jump::Distance
end
end
when 6 # Right
for i in 0...Jump::Distance
if passable?(self.x + i, self.y, 6)
@spaces[i] = i
return @spaces if i == Jump::Distance
end
end
when 8 # Up
for i in 0...Jump::Distance
if passable?(self.x, self.y - i, 8)
@spaces[i] = i
return @spaces if i == Jump::Distance
end
end
end
end
...Maybe I wrote that a little oddly, correct me if you know a better
functional method.

Anyways, next I test it with 'print(jump_dist)' whenever the player
'jumps' and it returns 0...3 (3 is Jump:istance, BTW)

So basically, instead of returning an array, it returns a Range.

How do I get this to return me an array of only passable 'spaces', and
secondly how do I pull the highest value out of that array?
--
Posted via http://www.ruby-forum.com/.

Kain Nobel, Jul 16, 2008

2. David A. BlackGuest

Hi --

On Wed, 16 Jul 2008, Kain Nobel wrote:

> Okay, so I wrote a script that'll allow the game player to jump with the
> touch of a button. This script, I wanted a method that'll adjust the
> distance in which
> the game player jumps, based on the farthest passible tile. To define
> the method, I used a 'for i' statement with 0 to the max distance, for
> each passible 'space' he can jump, I push the value into an array named
> '@spaces', respectively.
>
>
Code (Text):
def jump_dist
>    @spaces = []
>    case @direction
>    when 2 # Down
>      for i in 0...Jump::Distance
>        if passable?(self.x, self.y + i, 2)
>          @spaces[i] = i
>          return @spaces if i == Jump::Distance
>        end
>      end
>    when 4 # Left
>      for i in 0...Jump::Distance
>        if passable?(self.x - i, self.y, 4)
>          @spaces[i] = i
>          return @spaces if i == Jump::Distance
>        end
>      end
>    when 6 # Right
>      for i in 0...Jump::Distance
>        if passable?(self.x + i, self.y, 6)
>          @spaces[i] = i
>          return @spaces if i == Jump::Distance
>        end
>      end
>    when 8 # Up
>      for i in 0...Jump::Distance
>        if passable?(self.x, self.y - i, 8)
>          @spaces[i] = i
>          return @spaces if i == Jump::Distance
>        end
>      end
>    end
>  end
>
> ...Maybe I wrote that a little oddly, correct me if you know a better
> functional method.

Well, here's an untested rewrite that might save some space:

def jump_dist
spaces = []

0.upto(Jump:istance-1) do |i|
pass = case @direction
when DOWN then passable?(self.x, self.y + i, 2)
when LEFT then passable?(self.x - i, self.y, 4)
when RIGHT then passable?(self.x + i, self.y, 6)
when UP then passable?(self.x, self.y - 1, 8)
end
if pass
spaces = i
end
end

return spaces
end

(I've turned @spaces into spaces, which is better unless you really
need it as an instance variable.)

> Anyways, next I test it with 'print(jump_dist)' whenever the player
> 'jumps' and it returns 0...3 (3 is Jump:istance, BTW)
>
> So basically, instead of returning an array, it returns a Range.
>
> How do I get this to return me an array of only passable 'spaces', and
> secondly how do I pull the highest value out of that array?

The reason it's returning a range is that your range is exclusive. The
range (0...Jump:istance) doesn't include Jump:istance. Therefore,
the return statements never get executed. So what's returned, instead,
is the value of the whole for statement, which is the range itself.

To get the last element of an array: array[-1].

David

--
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See http://www.rubypal.com for details and updates!

David A. Black, Jul 16, 2008

3. Kain NobelGuest

Cool, that works wonders! Thanks David! *Adds special thanks to David in
credit*

I tried posting this in another forum and everybody wanted me to copy
someone else's script!
--
Posted via http://www.ruby-forum.com/.

Kain Nobel, Jul 17, 2008