How do I remove rows with NaNs from my raw data?

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Tessa 2014-11-18

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评论： Guillaume 2014-11-25

I have opened my excel data with xlsread and would like to remove all rows containing a NaN. Is there a possibility to do this at once? my data looks like this:

information blabla NaN NaN information blabla NaN NaN

NaN NaN NaN

Mydata Mydata Mydata My Data Mydata Mydata Mydata My Data Mydata Mydata NaN My Data Mydata Mydata Mydata My Data Mydata Mydata Mydata NaN Mydata Mydata Mydata My Data

It´s a cell array in case that matters :)

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Guillaume 2014-11-18

It does matter greatly that it's a cell array. Other than the NaNs, what's in the cell array? strings?, matrices? or just scalars?

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Answer 1

Giorgos Papakonstantinou 2014-11-18

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I assume that your data are of nx1 or 1xn size. Then to delete the use this:

data(isnan(data)) = [];

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Guillaume 2014-11-18

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This works as long as each element of the cell array is a scalar.

It won't work on:

data = {'info', [1 2 3 4 NaN], NaN, 5};

Tessa 2014-11-25

Thanks for the response. It is a mixture of numbers, dates and text. So both are not working... Is there a way to change the cell array in something numeric eventhough it is not all numbers?

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Answer 2

Guillaume 2014-11-25

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Tessa, try this:

c={'sometext', NaN, 12.5
   'othertxt', 45, 12
   NaN, 'blah', 7
   48, 78, 'aaa'} %example 
nanrows = any(cellfun(@(e) isnumeric(e) && isnan(e), c), 2);
c(nanrows, :) = []

It will work as long as you don't have a matrix of numbers in a cell. If you do, replace the

isnan(e)

by

any(isnan(e(:)))

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Tessa 2014-11-25

I´m feeling like a huge beginner at the moment :/ The result is: nanrows containing a logical filled with ones. And my original cell raw data now being a empty cell. I don´t understand what I´m doing wrong. What does the e mean?

Anyhow, I found a way around it and don´t need to do this anymore, but might be usefull in the future :)

Guillaume 2014-11-25

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If you get an empty cell, that means each row must contain at least one NaN.

I find it a bit odd to discard a whole row if there's just one NaN in it, but that's what you requested: "remove all rows containing a NaN".

The @(e) isnumeric(e) && isnan(e) is an anonymous function where e is just a placeholder name for any cell of the cell array. This is equivalent to:

function out = anonymousfunction(e)
   out = isnumeric(e) && isnan(e);
end

Obviously, you could use any name you want instead of e.

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