Variable problem

chrisglasier · 26 Jan 2011, 06:29

Please would someone be kind enough to show me how to sort out this snippet?


def kf(time)
keyframes = {}
model = Sketchup.active_model
d = model.attribute_dictionaries['kframes']
d.each_pair do | key,value |
a =  1
value.each do | v |
if v.nil?
v = [[1,0,0],0]
end
v << time * a
a += 1
end
keyframes[key] = value
end
return keyframes
end

When I puts the v's all are correct, but value returns the previously nil v' s to nil. Just cannot see why!

Thanks

thomthom · 26 Jan 2011, 07:26

It doesn't work as you expect because you are not changing the content of the array. You're dealing with a local copy.
I changed your loop to use .map - that should work. (untested)

<span class="syntaxdefault"><br />def kf</span><span class="syntaxkeyword">(</span><span class="syntaxdefault">time</span><span class="syntaxkeyword">)<br /></span><span class="syntaxdefault">  keyframes </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">{}<br /></span><span class="syntaxdefault">  model </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> Sketchup</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">active_model<br />  d </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> model</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">attribute_dictionaries</span><span class="syntaxkeyword">[</span><span class="syntaxstring">'kframes'</span><span class="syntaxkeyword">]<br /></span><span class="syntaxdefault">  d</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">each_pair do </span><span class="syntaxkeyword">|</span><span class="syntaxdefault"> key</span><span class="syntaxkeyword">,</span><span class="syntaxdefault">value </span><span class="syntaxkeyword">|<br /></span><span class="syntaxdefault">    a </span><span class="syntaxkeyword">=</span><span class="syntaxdefault">  1<br />    value</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">map do </span><span class="syntaxkeyword">|</span><span class="syntaxdefault"> v </span><span class="syntaxkeyword">|<br /></span><span class="syntaxdefault">      if v</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">nil</span><span class="syntaxkeyword">?<br /></span><span class="syntaxdefault">        v </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">[[</span><span class="syntaxdefault">1</span><span class="syntaxkeyword">,</span><span class="syntaxdefault">0</span><span class="syntaxkeyword">,</span><span class="syntaxdefault">0</span><span class="syntaxkeyword">],</span><span class="syntaxdefault">0</span><span class="syntaxkeyword">]<br /></span><span class="syntaxdefault">      end<br />      v </span><span class="syntaxkeyword"><<</span><span class="syntaxdefault"> time </span><span class="syntaxkeyword">*</span><span class="syntaxdefault"> a<br />      a </span><span class="syntaxkeyword">+=</span><span class="syntaxdefault"> 1<br />      v<br />    end<br />    keyframes</span><span class="syntaxkeyword">[</span><span class="syntaxdefault">key</span><span class="syntaxkeyword">]</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> value<br />  end<br />  return keyframes<br />end<br /></span>

chrisglasier · 26 Jan 2011, 07:43

@thomthom said:

It doesn't work as you expect because you are not changing the content of the array. ....

Thanks but I am sorry to say it doesn't work at all.

Also my original code successfully adds the time to each ( v) array, it only seems the nil block is being ignored by value.

So I don't know ...

chrisglasier · 26 Jan 2011, 07:58

.... but map does work if there aren't any nil elements in the value arrays.

thomthom · 26 Jan 2011, 08:24

@chrisglasier said:

Thanks but I am sorry to say it doesn't work at all.

sorry, should be .map!

@chrisglasier said:

Also my original code successfully adds the time to each (v) array, it only seems the nil block is being ignored by value.

Yes, because nil is immutable.

TIG · 26 Jan 2011, 09:25

value.each do | v |
if v.nil?
  v = [[1,0,0],0]
end
v << time * a
a += 1
end
keyframes[key] = value
end

looks through the contents of 'value' and assigns some values to elements in array 'v', then it sets the keyframes[key] back to be value ???
Don't you want to modify 'key'?
Why don't you use keyframes[key] = v ???

chrisglasier · 26 Jan 2011, 09:54

@tig said:

value.each do | v |
> if v.nil?
>   v = [[1,0,0],0]
> end
> v << time * a
> a += 1
> end
> keyframes[key] = value
> end

looks through the contents of 'value' and assigns some values to elements in array 'v', then it sets the keyframes[key] back to be value ???

Don't you want to modify 'key'?
Why don't you use keyframes[key] = v ???

Value is an array of arrays (like [[1,0,0],0]). So v is one of those. I am sure it is caused by the nil block? (immutable??). Perhaps I should make a new array from the v's because they are OK.

I will try that later or tomorrow.

Thanks for your help.

TIG · 26 Jan 2011, 10:02

In which case

  ...
  new_value = []
  value.each do | v |
    if v ### ??? ### isn't this what you want ?***
      v << time * a
    else ### OR it's nil
      v = [[1,0,0],0]
    end ### ***if NOT then revert to your format...
    new_value << v
    a += 1
  end
    keyframes[key] = new_value
  end

chrisglasier · 26 Jan 2011, 10:22

@tig said:

In which case

  ...
>   new_value = []
>   value.each do | v |
>     if v ### ??? ### isn't this what you want ?***
>       v << time * a
>     else ### OR it's nil
>       v = [[1,0,0],0]
>     end ### ***if NOT then revert to your format...
>     new_value << v
>     a += 1
>   end
>     keyframes[key] = new_value
>   end
>

Yes that looks good;I guess I can use v.is_a?(Array) for the if bit as the nil candidates are just empty elements.

Thanks to you both ...

TIG · 26 Jan 2011, 10:28

if v returns true if v is not nil or not []
The else then takes it's 'converse' i.e. it is nil OR []
I'm not clear about how a good or bad entry for 'value >>> v' might actually 'look' in your code...

chrisglasier · 26 Jan 2011, 11:34

@tig said:

I'm not clear about how a good or bad entry for 'value >>> v' might actually 'look' in your code...

<span class="syntaxdefault">new_value </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">[]<br /></span><span class="syntaxdefault">            value</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">each do</span><span class="syntaxkeyword">|</span><span class="syntaxdefault"> v </span><span class="syntaxkeyword">|<br /></span><span class="syntaxdefault">                if </span><span class="syntaxkeyword">!</span><span class="syntaxdefault">v</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">is_a</span><span class="syntaxkeyword">?(Array)<br /></span><span class="syntaxdefault">                    v </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">[[</span><span class="syntaxdefault">1</span><span class="syntaxkeyword">,</span><span class="syntaxdefault">0</span><span class="syntaxkeyword">,</span><span class="syntaxdefault">0</span><span class="syntaxkeyword">],</span><span class="syntaxdefault">0</span><span class="syntaxkeyword">]<br /></span><span class="syntaxdefault">                end<br />                v </span><span class="syntaxkeyword"><<</span><span class="syntaxdefault"> time </span><span class="syntaxkeyword">*</span><span class="syntaxdefault"> a<br />                a </span><span class="syntaxkeyword">+=</span><span class="syntaxdefault"> 1<br />                new_value </span><span class="syntaxkeyword"><<</span><span class="syntaxdefault"> v<br />            end<br />            keyframes</span><span class="syntaxkeyword">[</span><span class="syntaxdefault">key</span><span class="syntaxkeyword">]</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> new_value</span>

I did it like this in the end as both types of v have time added. Anyway it works which is good! Thanks again.

The empty elements currently are needed to delay certain rotations - like a kick at the end of a run. I have a mechanism to modularise the animation. I want to leave that until later.