removing entire row in cell array if first column is a NaN
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My data matrix (after reading into matlab with xlsread) contains many rows of string and numerical data, and at the end, there sometimes exists several rows of "NaN"s
I want to delete these specific rows but can't seem to do it properly.
I've tried q=cellfun(@(x) all(isnan(x)),myMatrix); myMatrix(q); but the result is no longer a cell
I've tried findNan=isnan(myMatrix(:,1)) to find the index of the row containing the NaN's to kill it, but it gives an error: ??? Undefined function or method 'isnan' for input arguments of type 'cell'.
Any assistance is appreciated! Thanks :)
2 Comments
Walter Roberson
on 6 Jun 2012
xlsread() can return 3 matrices, one for numeric, one for text, one for raw. Which one are you working with? To get the mix of numeric and text you must be working with raw ?
Accepted Answer
Walter Roberson
on 6 Jun 2012
myMatrix( cellfun( @(C) isnumeric(C) && isnan(C), myMatrix(:,1) ), :) = [];
3 Comments
Walter Roberson
on 6 Jun 2012
You have cells that contain strings; strings fail the isnumeric() test, and the && operator does not go on to the second test if the first test fails. isnan() is thus only applied to numeric values, and you only have one numeric value per cell so isnan() will return a scalar value, so you do not need any(). If you left off the isnumeric() test, then isnan() would be applied to the strings; it is well defined on strings but it returns one value per character.
An alternate coding should be
myMatrix( cellfun( @(C) any(isnan(C)), myMatrix(:,1) ), :) = [];
On the other hand, if somehow the matrix could contain other data types in the cells, then the isnumeric() version would be safer. Safer yet would be
myMatrix( cellfun( @(C) isnumeric(C) && any(isnan(C(:))), myMatrix(:,1) ), :) = [];
which allows for the possibility that a numeric array might have slipped in
More Answers (1)
the cyclist
on 6 Jun 2012
Does this do what you want?
% Some made-up data
c = num2cell([1 1; 2 2; NaN NaN]);
% Find the rows with all NaN
indexToRowToDrop = all(arrayfun(@(x)isnan(x{:}),c),2)
% Drop the bad rows
c(indexToRowToDrop,:) = [];
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