I have a question related to cell arrays. How do I delete a specific row by checking the first element of that row?

Here I have a matrix, and I want to eliminate the rows which start with '$', please go through the excel file that I have attached.

What I'm expecting is this as ouput, which I may write it to another excel file:

'c' '1' '2.400000000000000E+00' '2.400000000000000E+00' '2.400000000000000E+00' 'c' '2' '3.360000000000000E+00' '2.400000000000000E+00' '2.400000000000000E+00' 'c' '3' '4.320000000000000E+00' '2.400000000000000E+00' '2.400000000000000E+00' 'c' '4' '5.280000000000001E+00' '2.400000000000000E+00' '2.400000000000000E+00' 'c' '5' '6.240000000000000E+00' '2.400000000000000E+00' '2.400000000000000E+00'

[Gurubasav Yellur]

I tried with this following code, but the it seems that it is not entering the if condition.

A = importdata('trialdata.xlsx');

L = length(A); n = 1; while n <= L disp('inside the while'); if A{n,1} =='$' A(n,:) =[]; end n = n+1; end

[Swapnil]

Hi, Try with this,

[~,~,Cells] = xlsread('trialdata.xlsx');

Cells(find(~cellfun('isempty',strfind(Cells(:,1),'$'))),:) = [];

[Gurubasav Yellur]

Dear Swapnil,

Thank you very much for that block of code! It works fine. I also wanted to completely delete the 6th and 7th columns. In fact, without explicitly mentioning these particular column numbers I want to eliminate all those columns which contain 'NAN'.

[Swapnil]

Hi, I think this will work for you.

[~,~,Cells] = xlsread('trialdata.xlsx');

Cells(find(~cellfun('isempty',strfind(Cells(:,1),'$'))),:) = [];

indexes = [];

for idx = 1:size(Cells,2)

    a = cellfun(@isnan,Cells(:,idx),'UniformOutput',false);

    if( all(cellfun(@any,a)))

         indexes = [indexes,idx];   

    end

end

Cells(:,indexes) = [];

Answer 1

[Guillaume]

To remove elements from a matrix and cell arrays you assign [] to them.

To find strings that match you use strcmp. You only want to do the comparison with the first column, so you use the () indexing for that.

Therefore:

c = {'$', '$', 'wmesh', '[geo_Meshio.c]', '--';
     '$', 'c', '216', '', '';
     '$', 'r', '6', '', '';
     '$', 'x', '119', '' '';
     '$', '$ Vertices', '', '', '';
     'c', '1', '2.400000000000000E+00', '2.400000000000000E+00', '2.400000000000000E+00';
     'c', '2', '3.360000000000000E+00', '2.400000000000000E+00', '2.400000000000000E+00';
     'c', '3', '4.320000000000000E+00', '2.400000000000000E+00', '2.400000000000000E+00';
     'c', '4', '5.280000000000001E+00', '2.400000000000000E+00', '2.400000000000000E+00';
     'c', '5', '6.240000000000000E+00', '2.400000000000000E+00', '2.400000000000000E+00'};
c(strcmp(c(:, 1), '$'), :) = []

[Gurubasav Yellur]

Your code works perfect and that's what I am looking for, but I am not able to get the same result when I am importing that excel file data in a variable A= {}.

Here is what I tried:

A={}; A = importdata('trialdata.xlsx') A(strcmp(A(:, 1), '$'), :) = []

---------------------------------------------------

P.S You overlooked the two double quotes that are in the 6th and 7th columns respectively.

[Guillaume]

Right, to import your excel file, use the 2nd output of xlsread (or even the 3rd output).

[~, c] = xlsread('trialdata.xlsx');

Optionally, remove the quotes surrounding each elements:

c = cellfun(@(s) strrep(s, '''', ''), c, 'UniformOutput', false);

You can then remove the rows that start with '$' (if you don't remove the quotes, it's '''$'''):

c(strcmp(c(:, 1), '$'), :) = [];

And to remove empty columns:

c(:, all(strcmp(c, ''))) = [];