Extract data from multiple excel files
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I am trying to extract data from a specific column from multiple excel files and save this columns in one table
D = 'C:\Users\Desktop\Analyze\';
for k=1:250
file = sprintf('Data_%d.xlsx',k);
filename = strcat('C:\Users\TR8E1MQ\Desktop\Analyze\',file);
x = xlsread(filename);
T = x(:,7);
end
This how I am extracting one column. I want to keep those and keep adding more values from other excel files.
采纳的回答
Guillaume
2020-1-10
I would recommend you use fullfile instead of strcat to build paths. This way you don't have to worry about path separators.
Assuming that all files have the number of rows, this is how I'd do it:
source_folder = 'C:\Users\Desktop\Analyze'; %much more meaningful name than D
numfiles = 250;
data = []; %will be preallocated upon reading the first file, once we know the size of a column
for fileidx = 1:numfiles
filedata = readmatrix(fullfile(source_folder, sprintf('Data_%d.xlsx', fileidx)));
if fileidx == 1
data = zeros(size(filedata, 1), numfiles); %preallocate to the height of columns x num files
end
data(:, fileidx) = filedata(:, 7); %copy column 7 into output matrix
end
end
10 个评论
Mariana
2020-1-10
Guillaume
2020-1-10
Yes, since all columns of a matrix must have the same number of rows.
Otherwise, you'd have to pad the shorter rows / crop the longer ones / not use a matrix for storage. Any of these is possible.
Mariana
2020-1-10
Guillaume
2020-1-10
A cell array, but be aware that a cell array is more complicated to use.
So, have your files got the same number of rows or not?
Mariana
2020-1-10
In that case:
source_folder = 'C:\Users\Desktop\Analyze'; %much more meaningful variable name than D
numfiles = 250;
data = cell(1, numfiles); %since all files have different number of rows. Store the desired columns in a cell array
for fileidx = 1:numfiles
filedata = readmatrix(fullfile(source_folder, sprintf('Data_%d.xlsx', fileidx)));
data{fileidx} = filedata(:, 7); %copy desired column in corresponding element of the cell array
end
Mariana
2020-1-10
Guillaume
2020-1-10
For versions prior to R2019a, replace readmatrix by xlsread. Rest of the code would be the same.
Mariana
2020-1-11
Nusrat Chowhdury
2022-3-30
What is the code if I wanna take multiple columns of each excel file in the same way?
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