Problem renaming variable in loop

Question

amir 2023-7-5

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1992043-problem-renaming-variable-in-loop

编辑： Nathan Hardenberg 2023-7-6

In the last loop, suppose I want to get the Hilbert transform from the 150 variables Is1...Is150 in the commented part of the loop.

What should I do????

clc

clear

close all

Rf1=[0.001 10 50 100 200];

L_line1=[4 50 100 140 150 196];

tetta1=[10 -15 20 30 40];

%% read data

for i=1:150

if i<=30

f1(i)=Rf1(1);

elseif i<=60

f1(i)=Rf1(2);

elseif i<=90

f1(i)=Rf1(3);

elseif i<=120

f1(i)=Rf1(4);

else

f1(i)=Rf1(4);

end

for i=1:30

if i<=5

f2(i)=L_line1(1);

elseif i<=10

f2(i)=L_line1(2);

elseif i<=15

f2(i)=L_line1(3);

elseif i<=20

f2(i)=L_line1(4);

elseif i<=25

f2(i)=L_line1(5);

else

f2(i)=L_line1(6);

end

for i=1:150

f1_1=num2str(f1(i));

prt1=strcat(f1_1,'_');

for i2=1:30

f2_2=num2str(f2(i2));

prt2=strcat(f2_2,'_');

for i3=1:5

f3_3=num2str(tetta1(i3));

prt3=strcat(f3_3,'\');

print=strcat('C:\Users\MASHHADSERVICE\Downloads\data\SPS\S_',prt1,prt2,prt3,'Fi_',prt1,prt2,f3_3,'.mat');

load(print);

If=cell2mat(Y);

If_1=If(1999:2401);

eval(['If', num2str(i) , ' =If_1;']);

print1=strcat('C:\Users\MASHHADSERVICE\Downloads\data\SPS\S_',prt1,prt2,prt3,'Si_',prt1,prt2,f3_3,'.mat');

load(print1);

Is=cell2mat(Y);

Is_1=Is(1999:2401);

eval(['Is', num2str(i) , ' =Is_1;']);

end

load('C:\Users\MASHHADSERVICE\Downloads\data\SPS\S_0.001_4_10\time.mat');

t1=cell2mat(Y);

time=t1(2001:2400);

%% D

for i=1:150

eval(['Is1', num2str(i) , '= hilbert'(eval(['Is', num2str(i)]))]);

end

3 个评论
显示 1更早的评论隐藏 1更早的评论

KALYAN ACHARJYA 2023-7-5

编辑：KALYAN ACHARJYA 2023-7-5

Additionally, you may utilize the piecewise function, which will help reduce the number of if-else statements.

https://in.mathworks.com/help/symbolic/sym.piecewise.html

John D'Errico 2023-7-5

编辑：John D'Errico 2023-7-5

@amir

Please don't use an answer to do nothing more than say thanks to someone unspecified. And then worse, ACCEPT IT AS THE CORRECT ANSWER.

I deleted your acepted answer, since it was not in fact even remotely an answer. Learn to use comments.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Nathan Hardenberg 2023-7-5

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1992043-problem-renaming-variable-in-loop#answer_1267608

编辑：Nathan Hardenberg 2023-7-6

在 MATLAB Online 中打开

Having 150 variables all having to do with one thing is not good coding. You should use a matrix/array/cells instead. Also using eval() to assign or call a variable is not very good as well. You should avoid those practices.

But here is hopefully a possible solution, instad of your for-loop:

Is1 = -1; Is2 = 4; Is3 = 3; Is4 = 2; % "your" variables
N = 4;  % N=150 in your example
xr = zeros(1,N);  % predefine matrix
for i=1:N
    xr(i) = eval(['Is', num2str(i)]);  % write all your variables into the matrix
end
X = hilbert(xr)  % do the hilbert transform
X = 
  -1.0000 - 1.0000i   4.0000 - 2.0000i   3.0000 + 1.0000i   2.0000 + 2.0000i

Edit: To be more clear, since @Stephen23 posted a very useful link in the comments. This style of coding using eval() should not be done! My answer is just a working solution, with the given situation, without changing the intire code. But changing the intire code would be recommended with reasons written in the link.