MATLAB Answers

Indexing in for loop in order to remove non-zero and nan entries from vectors

1 ビュー (過去 30 日間)
hello_world
hello_world 2016 年 5 月 18 日
編集済み: hello_world 2016 年 5 月 18 日
Hello Friends,
I have the following code:
P = [1, 0, 3];
Q = [0, 4, 5];
% These AB, CD, EF are just for illustration purpose. They could be any to make AB, CD , EF equal size vectors.
AB = [P + Q]; % A vector
CD = [P - Q]; % A vector
EF = [P ./ Q]; % A vector
% Now I want to pass above compute vectors AB, CD, EF in for loop. I try as follows:
M = {'AB', 'CD', 'EF'};
for i = 1:length(M)
P1 = P(M{i}~=0); %It removes those elements of P which correspond to 0 entries in M.
t = M{i}; %Create a temporary variable.
M = t(M{i}~=0); %It removes 0 entries from M.
P = P1(~isnan(M(i))); %It removes those elements of P which correspond to NaN entries in M.
M = t(~isnan(M(i))); %It removes NaN entries from M.
if strcmp(M, 'AB')
f = f(P,M);
elseif strcmp(M, 'CD')
f = g(Q,M);
elseif strcmp(M, 'EF')
f = h(R,M);
end
end
This code is not computing P1, t, M, P values properly. For example the following line of code takes M{i} = AB for i = 1, but gives totally wrong answer.
I have tried to change {} to () and [], etc., but nothing works. I will appreciate any advice.
P1 = P(M{i}~=0);

回答 (1 件)

Todd Leonhardt
Todd Leonhardt 2016 年 5 月 18 日
編集済み: Todd Leonhardt 2016 年 5 月 18 日
The problem appears to be that your loop changes M into something with a single element on the first pass through, but then tries to access the 2nd element on the 2nd pass through.
On the first pass through (i=1), this following line sets M equal to 'AB'
M = t(M{i}~=0)
Then this line mutates it further to just 'A':
M = t(~isnan(M(i)));
So on the 2nd pass through your loop (i=2), this line tries to access the 2nd element in the M cell array, but there is only 1 element:
P1 = P(M{i}~=0);
  1 件のコメント
hello_world
hello_world 2016 年 5 月 18 日
I know, and I am trying to fix it, but still no success. In
P1 = P(M{i}~=0);
M{i} is AB, a cell, while P is double. If I change AB to cell to double, it does not work. It should actually take values stored in AB, and not just characters AB.

サインインしてコメントする。

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by