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Index › Programming Questions & Help › Syntax Questions › Extend a 2D array
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Extend a 2D array (Read 781 times)
FelTheCat
Extend a 2D array
Nov 18th, 2007, 5:47am  
How can I extend a 2D array? I've try this :

String[][] LSystem2D = new String[7][11];

LSystem2D = (String[][]) expand(LSystem2D, LSystem2D.length+1);
LSystem2D = (String[][]) expand(LSystem2D, LSystem2D[0].length+1);
println(LSystem2D.length); // 12
println(LSystem2D[0].length); // 11

Look like it's working for the second parameter(array) but not for the first. What do I missunderstand? (or not understand at all)

Also, what if I would like to append a value instead? Thx a lot!
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steven
Re: Extend a 2D array
Reply #1 - Nov 18th, 2007, 9:27am  
For the expand, this will help (look at Fry's post):
http://processing.org/discourse/yabb_beta/YaBB.cgi?board=Syntax;action=display;num=1193701437;start=5#5

To append an array, you need a cast.
Here's what you need to do (code by JohnG):

Code:

int[][] test = {{1,2},{3,4}};
test = (int[][])append(test, new int[]{5,6});
println(test.length);


Code from -> http://processing.org/discourse/yabb_beta/YaBB.cgi?board=Syntax;action=display;num=1193515933
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FelTheCat
Re: Extend a 2D array
Reply #2 - Nov 18th, 2007, 4:30pm  
Look ok for a simple array but don't work for a 2D array.. Sad
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steven
Re: Extend a 2D array
Reply #3 - Nov 18th, 2007, 6:05pm  
Sorry, I misread your post.

Your code for expanding arrays worked.
I believe that there is just a little logic problem here:

Quote:
LSystem2D = (String[][]) expand(LSystem2D, LSystem2D[0].length+1);


You're expanding the outer array (LSystem2D) to the size of the inner array (LSystem2D[0]).
So your outer array becomes (size of LSystem2D[0]) 11 + 1 which equals 12. So the code works.

I believe you want to expand the inner array. To do that, you need to specify the array you want to expand.
Code:

 LSystem2D[0] = (String[]) expand(LSystem2D[0], LSystem2D[0].length+1);


Take a look at the code below:

Code:

String[][] LSystem2D = new String[7][11];

println(LSystem2D.length); // 7
LSystem2D = (String[][]) expand(LSystem2D, LSystem2D.length + 1);
println(LSystem2D.length); // 8

println(LSystem2D[0].length); // 11
LSystem2D[0] = (String[]) expand(LSystem2D[0], LSystem2D[0].length+1);
println(LSystem2D[0].length); // 12
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FelTheCat
Re: Extend a 2D array
Reply #4 - Nov 18th, 2007, 7:17pm  
Thx a lot dude! It was a problem with the typecasting.
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