classify data from csv fil

Question

Khadija Al Jabri 2018-5-11

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/400323-classify-data-from-csv-fil

评论： Star Strider 2018-5-11

采纳的回答： Star Strider

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hello everyone

I want to read data from csv file and classify these data. my csv look like this:

0
0.139999945
0.209999918
12.86283386
0
-0.649996554
-2.609774285
-114.4151
...

its [154*1][row*col], I want to classify these data as

(if data = 0 then write 0 in the second column)
(if 0<data<=45 then print 1)
(if 45<data<=90 then print 2)
(if 0>data>=-45 then print 3)
(if -45>data>=-90 then print 4)

I don't know what should I write in the condition statement! the following is my attempt but it doesn't give the desired output.

M = csvread('imu.csv')
[rows cols] = size(M);
for k = 1:length(M)   
    if M == 0
        A=0;
    elseif 0<M<=45
        A=1;
    elseif 45<M<=90
        A=2;
    elseif 0>M>=-45
        A=3;
    else
        A=4;
    end
end
csvwrite('imu2.csv',A);

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Image Analyst 2018-5-11

编辑：Image Analyst 2018-5-11

"write 0 in the second column" of what , A or M? If A, then what is in the first column of A?

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Answer 1

Star Strider 2018-5-11

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The loop and if block are not necessary.

I would simply do this:

M = randn(10, 1);                           % Create Vector
M = [M zeros(size(M))];                     % Preallocate
M(M(:,1) > 0,2) = 1;
M(M(:,1) < 0,2) = 2;

That initially creates the second column as zeros, then sets the second column according to the positive and negative values in the first column.