How to exclude/extract empty rows/columns in a table?

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Ivan Mich
Ivan Mich 2023-2-8
回答： Voss 2023-2-16
Hello,
I have a question about a code. I have a table with 8 columns (I use readtable command). In this file there are scattered blanks from column 5 to 8, and from column 1 to column 4.
I would like two files to be created from this file. one containing the filled (without blanks) columns 1 through 4, and the other file containing the filled without blanks columns 5 through 8.
I attach both the input (test_file.txt) and the two outputs (output1.txt & output2.txt) that I would like to have.
Could you please help me?

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回答（2 个）

KSSV
KSSV 2023-2-8
编辑：KSSV 2023-2-8
T = readtable('https://in.mathworks.com/matlabcentral/answers/uploaded_files/1288860/test_file.txt');
% Remove empty rows
idx = cellfun(@isempty,T.(1)) ;
T(idx,:) = [] ;
%
idx = isnan(T.(6)) ;
M = (1:height(T))' ;
idr = diff(find([1;diff(idx);1]));
D = mat2cell(M,idr(:),size(M,2)) ;
iwant = cell(length(D),1) ;
for i = 1:length(D)
iwant{i} = T(D{i},:) ;
end
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Ivan Mich
Ivan Mich 2023-2-10
the problem is that your script separates only the code that have elements in columns 1-4 (and nan elements in the other columns of each row) into multiple files. the problem is that I would like to have a separated file for rows like row 11 of my input file (test_file.txt attached), that have nan elements in columns 1-4 and in columns 5-8 have numbers/elements..
Finally the purpose is to have two output files (output1.txt & output2.txt attached in this commend). I do not want to include rows like n.6 and n.7 in my input file that have completed all the columns with numbers/elements.
Could you please help me?

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Voss
Voss 2023-2-16
Ran in:
% read input file into table T
T = readtable('test_file.txt');
% get a logical matrix saying whether each element of the table is missing
% (NaN for numerics, '' for cell arrays of chars)
ism = ismissing(T);
% only output rows that have some missing value
rows_to_use = any(ism,2);
% rows without any missing value in the first 4 columns will go to output1
rows_for_output1 = ~any(ism(:,1:4),2);
% create two new tables from the original
output1 = T(rows_to_use & rows_for_output1,:);
output2 = T(rows_to_use & ~rows_for_output1,:);
% write the tables to their respective output files
writetable(output1,'output1.txt','Delimiter','\t','WriteVariableNames',false)
writetable(output2,'output2.txt','Delimiter','\t','WriteVariableNames',false)
% check the output files
type output1.txt
SAINT 38.6 22.3 10 NaN NaN NaN MILAN 34 24 30 NaN NaN NaN MILAN 39.3 26.8 30 NaN NaN NaN MILAN 37.5 21 69 NaN NaN NaN PARIS 40.5 25 5 NaN NaN NaN FLORIDA 37.5 21 31 NaN NaN NaN FLORIDA 37.5 24 602 NaN NaN NaN FLORIDA 39.5 21 549 NaN NaN NaN NAPOLI 37.5 21 205 NaN NaN NaN
type output2.txt
NaN NaN NaN CHINA 40.5 25 3.5

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