Concatenation of arrays of structure

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pietro
pietro 2014 年 11 月 1 日
コメント済み: Image Analyst 2014 年 11 月 1 日
Hi all
I have to concatenate the field of an array of structure. Here a simple example:
a=struct('a',[]);
a(1).a=[1:5;6:10];
a(2).a=[10:50;60:100]; [EDITED, should be:] [10:10:50; 60:10:100]
Results:
Concatenated_afield=[1,2,3,4,5,6,7,8,9,10;10,20,30,40,50,60,70,80,90,100]
Thank you
Best regards
  1 件のコメント
Image Analyst
Image Analyst 2014 年 11 月 1 日
You can't do that unless you change the step in (2) to be 10 instead of 1, or change (1) to be a 2-by-41 array like (2) is instead of a 2 by 5 array.

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採用された回答

Image Analyst
Image Analyst 2014 年 11 月 1 日
Try this:
% Construct sample data
s=struct('a',[]);
s(1).a=[1:5;6:10]
s(2).a=[10:10:50;60:10:100]
% Now concatenate:
t1 = s(1).a'
t2 = s(2).a'
output = [t1(:), t2(:)]'
In the command window:
t1 =
1 6
2 7
3 8
4 9
5 10
t2 =
10 60
20 70
30 80
40 90
50 100
output =
1 2 3 4 5 6 7 8 9 10
10 20 30 40 50 60 70 80 90 100
Note I didn't use the field name of "a" on a structure also called "a" - I think that's a very bad idea that will lead to confusion, so I named my structure "s".
  2 件のコメント
Image Analyst
Image Analyst 2014 年 11 月 1 日
Use a for loop
% Construct sample data
s=struct('a',[]);
s(1).a=[1:5;6:10]
s(2).a=[10:10:50;60:10:100]
s(3).a=[20:10:60;70:10:110]
% Now concatenate
for k = 1 : length(s)
this_t = s(k).a'
output(k, :) = this_t(:)';
end
output

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その他の回答 (2 件)

Jan
Jan 2014 年 11 月 1 日
編集済み: Jan 2014 年 11 月 1 日
a = struct('a',[]);
a(1).a = [1:5; 6:10];
a(2).a = [10:10:50; 60:10:100];
v = cat(2, a.a);
r = reshape(permute(reshape(v, 2, 5, 2), [3,2,1]), [2, 10]);

per isakson
per isakson 2014 年 11 月 1 日
編集済み: per isakson 2014 年 11 月 1 日
I assume that &nbsp [10:50;60:100] &nbsp should be &nbsp [10:10:50;60:10:100]
a=struct('a',[]);
a(1).a=[1:5;6:10];
a(2).a=[10:10:50;60:10:100];
>> cat( 1, transpose( a(1).a(:) ), transpose( a(2).a(:) ) )
ans =
1 6 2 7 3 8 4 9 5 10
10 60 20 70 30 80 40 90 50 100
&nbsp
And another try
transpose(cell2mat(arrayfun(@(s)reshape(transpose(s.a),[],1),a,'uni',false)))
ans =
1 2 3 4 5 6 7 8 9 10
10 20 30 40 50 60 70 80 90 100
And a for-loop
M = nan( length(a), length(a(1).a(:)) );
for jj = 1 : length( a)
M( jj, : ) = [ a(jj).a(1,:), a(jj).a(2,:) ];
end
xlswrite( filespec, M )
  8 件のコメント
per isakson
per isakson 2014 年 11 月 1 日
Because the for-loop is
  • easier to construct
  • easier to read and understand in three weeks from now
  • and - I guess - executes faster

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