Not overwriting array in if-elseif loop

2011 7 23
2 个回答
回答已采纳
7 次查看（30 天）

0 个投票

Hi,
I have the following code
for k = 1:length(yarray)-1
if yarray(k+1) <= A & yarray(k) >= A
M = [yarray(k) yarray(k+1) k k+1]
elseif yarray(k+1) >= A & yarray(k) <= A
M = [yarray(k) yarray(k+1) k k+1]
end
end
Where yarray is an array of y values in a plot, and A is the y value that I want to find corresponding x values to. I am expecting the if and elseif conditions to be satisfied 4 times, resulting in 4 M arrays. However, each time this is satisfied, M is overwritten. How can I come up with 4 different arrays which I can recall later?Let me know if this needs more clarification. Thanks!

请先登录，再回答此问题。

 采纳的回答

Oleg Komarov
Oleg Komarov 2011-7-23

0 个投票

Preallocate M before the loop and index it inside the loop:
M = zeros(length(yarray)-1,4);
for...
M(k,:) =
end

更多回答（1 个）

Jan
Jan 2011-7-23

0 个投票

y_le_A = (yarray <= A);
y_ge_A = (yarray >= A);
index = or(and(y_le_A(2:end), y_ge_A(1:end-1)), ...
and(y_ge_A(2:end), y_le_A(1:end-1)));
k = find(index);
M = transpose([yarray(k); yarray(k+1); k; k+1]);
The last line needs yarray to be a row vector.
I have the impression, that this can be simplified using a DIFF trick.

类别

在 帮助中心 和 File Exchange 中查找有关 Loops and Conditional Statements 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by