How can I use different array names in a loop?
显示 更早的评论
Hello,
Suppose I have 4 arrays as,
a_1_b;
a_2_b;
a_3_b;
a_4_b
all the arrays are of same size. I want to add something in the first column of each of the arrays, but I am not sure how to do this. as example:
for i=1:4
a_i_b(:,1)=a_i_b(:,1)+7
end
this is not the right way. Can anyone please show me the correct way?
Thanks!
采纳的回答
Azzi Abdelmalek
2013-6-11
编辑：Azzi Abdelmalek
2013-6-11
for i=1:4
evalin('base',sprintf('a_%d_b(:,1)=a_%d_b(:,1)+7',i,i))
end
%or
for i=1:4
data=7
evalin('base',[sprintf('a_%d_b(:,1)=a_%d_b(:,1)+',i,i) num2str(data)])
end
1 个评论
Jan
2013-6-11
Avoid EVAL and EVALIN in general. Both increase the komplexity and reduce the efficiency, and there are always cleaner and faster methods.
更多回答（3 个）
Jan
2013-6-11
See http://www.mathworks.com/matlabcentral/answers/57445-faq-how-can-i-create-variables-a1-a2-a10-in-a-loop: It is strongly recommended not to hide indices in the names of variables, but touse indices instead.
ab = cell(1, 4);
ab{1} = rand(2,3);
ab{2} = rand(2,3);
ab{3} = rand(2,3);
ab{4} = rand(2,3);
for k = 1:4
ab{k}(:,1) = ab{k}(:,1) + 7
end
Andrei Bobrov
2013-6-11
n = sprintf('a_%d_b,',1:4);
a_b = eval(['{',n(1:end-1),'}']);
a_b = cellfun(@(x)[x(:,1) + 7,x(:,2:end)],a_b,'un',0);
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