Seperate column into more columns: 90740x1 double array into 1511x64 something array

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awda 2014-4-8

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评论： Kelly Kearney 2014-4-8

采纳的回答： Kelly Kearney

Hello

i have a set of data 90740x1 double. meaning:

what i really want this to do is make a new matrix where i read every 1511 data from this row into a new row. example:

so from 1 to 1511 in column 1 in the new matrix...and from 1511 to 3023 into column 2 in the new matrix etc. etc.

i made a code, it only works for the first 1511 data but after that it displays an error about dimension.

n = 1; for i=1:length(kwh) kunder(:,1) = kwh(1:n:1511); end

so when u put: kunder(:,1) = kwh(1511:n:3023); under the first kunder it displays dimension error...

please help me figure this out..as i want to plot the 24 hour kwh usage data of customers consumption of electricity.

thank you

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Answer 1

Kelly Kearney 2014-4-8

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https://ww2.mathworks.cn/matlabcentral/answers/124986-seperate-column-into-more-columns-90740x1-double-array-into-1511x64-something-array#answer_132716

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Your code is erroring because of mismatched dimensions; when n = 2, 1:n:1511 expands to [1 3 5 ... 1511], which is only 756 elements in length. What you wanted was [1:1511]+1511*(n-1). But it would be more straighforward just using reshape.

x = rand(90740,1);
nrow = 1511;
ncol = ceil(length(x)/nrow);
x = [x; nan(ncol*nrow-length(x),1)];
x = reshape(x,nrow,ncol);

Note that you need to pad with NaNs or 0s or whatever is appropriate, since your number of elements isn't evenly divisible by 1511.

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awda 2014-4-8

Thank you, it really did work, it helped me :)

there is a small problem i dont understand now: when i divide 90740/1511 i should get 64 columns with 34 more data in the last part..but now i get 300+ more data in the column 65..with nan in the end.. any ideas if it is dividing the Column correctly or adding random data in ?

Kelly Kearney 2014-4-8

How do you figure that? 90740/1511 = 60.053, ie. 60 remainder 80. So you should end up with a 1511 x 61 array, with 80 elements in the final column.

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Answer 2

Azzi Abdelmalek 2014-4-8

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https://ww2.mathworks.cn/matlabcentral/answers/124986-seperate-column-into-more-columns-90740x1-double-array-into-1511x64-something-array#answer_132713

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Use reshape

reshape(A,1511,64)

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Azzi Abdelmalek 2014-4-8

This is because with 90740 elements you can't get a 1511x64 array which contains 96704 element

Azzi Abdelmalek 2014-4-8

在 MATLAB Online 中打开

What you can do is to add some nan to your final array

n=90740
A=rand(n,1);
m=ceil(90740/1511)*1511
A(end+1:m)=nan
out=reshape(A,1511,[])

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