How to read many csv files at once and then extract certain column from it?

Question

Anirban Mandal 2021-12-24

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1616985-how-to-read-many-csv-files-at-once-and-then-extract-certain-column-from-it

编辑： Anirban Mandal 2021-12-24

I have about 115 csv files with 9 columns and rows ranging from 10^6 to 10^7. I want to read all of them at once and extract the necessary columns from it later. I tried the following code below for combining them. But I am not being able to extract a certain column. Any suggestion?

clear 
clc
file=dir('*.csv');
num=length(file);
combined=cell(length(file),1);
for i=1:num
    combined{i}=xlsread(file(i).name);
end

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Answer 1

Walter Roberson 2021-12-24

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https://ww2.mathworks.cn/matlabcentral/answers/1616985-how-to-read-many-csv-files-at-once-and-then-extract-certain-column-from-it#answer_861375

在 MATLAB Online 中打开

file=dir('*.csv');
num=length(file);
combined = cell(num, 1);
for i=1:num
    combined{i}=xlsread(file(i).name);
end
desired_column = 7;
certain_column_cell = cellfun(@(C) C(:,desired_column), combined, 'uniform', 0);