Split array in 3 groups by using one column values
显示 更早的评论
Hi,
I would like to split my data in 3 groups based on the values in axis 1
x = < 25 i would like to get a 0
x = > 25 < 419 i would like to get a 1
x = > 419 i would like to get a 2
how can I do this?
% Clear memory
clear; close all;
% Load data
T=readtable('SC01001 (2018-11-23)15sec.csv','PreserveVariableNames',true)
x1=T(:,1); %Date
x2=T(:,2); % Time
y1=T(:,3); % Axis 1
if
y1 <25
y1 = 0
elseif
y1 25>y1<419
y1 = 1
elseif
y1 >419
y1 = 2
end
采纳的回答
You shouldnt use a vector in a if condition.
In your case, it would be more effective to use this
loc=find(y1<25);
y(loc)=0;
loc1=find(y1>25 & y1<419);
y(loc1)=1;
loc2=find(y1>419);
y(loc2)=2;
If you are new to matlab you might understand the problem better with a for loop.
for i=0:length(y1)
if(y1(i)<25)
y(i)=0;
elseif (y1(i)>25 & y1(i)<419)
y(i)=1;
else
y(i)=2;
end
end
I prefer to not rewrite any variable i am using until it is completely necessary.
Make sure you really need those intervals and consider what you have to do if y1=25 since in your original code it would not enter any if else condition
7 个评论
Ankit
2020-2-25
small correction in the first line of the for loop, i think by mistake you wrote 0 instead of 1.
Annick
2020-2-25
Annick
2020-2-25
Everything above the for loop works for me. This is the screen I get. Even when I try the xlsx file, i keep getting the same error message
Hello,
Thank you Ankit for your correction
There is a step missing:
x1=T(:,1); %Date
x2=T(:,2); % Time
y1=table2array(T(:,3)); % Axis 1
for i=1:length(y1)
if(y1(i)<25)
y(i)=0;
elseif (y1(i)>25 & y1(i)<419)
y(i)=1;
else
y(i)=2;
end
end
Make sure in future problems that you read the error and understand what it means, as that line missing is easily solvable. If you need matrix or vectors instead of table you can use table2array: https://es.mathworks.com/matlabcentral/answers/380821-how-to-convert-table-to-matrix
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