Read multiple CSV files from different folders uing readtable

13 ビュー (過去 30 日間)
Hello
I have to read multiple csv files from differnt folders on the same editor window to plot on the same figure.
I have tried sth like this
ds1 = datastore('*.csv');
T = readall(ds1);
buit this gives data for only the currecnt directory.
I have file paths p1 , p2 and p3 for each 3 folders and i want to read thoese files from the 3 folder,
I am stuck and appreciate your help
Thank you

採用された回答

Image Analyst
Image Analyst 2022 年 9 月 26 日
See the FAQ:
% Specify the folder where the files live.
myFolder = 'C:\Users\yourUserName\Documents\My CSV Files';
% Check to make sure that folder actually exists. Warn user if it doesn't.
if ~isfolder(myFolder)
errorMessage = sprintf('Error: The following folder does not exist:\n%s\nPlease specify a new folder.', myFolder);
uiwait(warndlg(errorMessage));
myFolder = uigetdir(); % Ask for a new one.
if myFolder == 0
% User clicked Cancel
return;
end
end
% Get a list of all files in the folder, and its subfolders, with the desired file name pattern.
filePattern = fullfile(myFolder, '**/*.csv'); % Change to whatever pattern you need.
theFiles = dir(filePattern);
for k = 1 : length(theFiles)
baseFileName = theFiles(k).name;
fullFileName = fullfile(theFiles(k).folder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
% Now do whatever you want with this file name,
% such as reading it in as a table.
thisTable = readtable(fullFileName);
end
  3 件のコメント
Bizuayehu Addisie Beyene
Bizuayehu Addisie Beyene 2022 年 9 月 26 日
I can see its printed on the command window... I am doing this and i have the follwoing error: K is 1 for this case...which was supposed to be length of files.... I am confused here ....
Thank you so much again
myFolder = p3;%'C:\Users\yourUserName\Documents\My Pictures';
% Get a list of all files in the folder with the desired file name pattern.
file= fullfile(myFolder, '*.CSV'); % Change to whatever pattern you need.
Files = dir(file);
B=zeros(198,1);% length(L(:,3)
for k = 1 : length(Files)
FileName = Files(k).name;
fullFileName = fullfile(Files(k).folder, FileName);
l = readtable(fullFileName);
B(:,k)=l{:,3}
end
histogram(B)
error: Unable to perform assignment because the
size of the left side is 198-by-1 and the
size of the right side is 6-by-1.
Error in seasonal_bubble_2014 (line 38)
B(:,k)=l{:,3}

サインインしてコメントする。

その他の回答 (2 件)

KSSV
KSSV 2022 年 9 月 26 日
thepaths = {p1,p2,p3} ;
for i = 1:3 % loop for ech folder
csvFiles = dir([thepaths{i},'\*csv']) ; % get ll csv files in the folder
N = length(csvFiles) ;
for j = 1:N % loop for each csv file
csvFile = fullfile(csvFiles(j).folder,csvFiles(j).name) ;
T = readtable(csvFile) ;
% do what you want
end
end
  6 件のコメント
Bizuayehu Addisie Beyene
Bizuayehu Addisie Beyene 2022 年 9 月 26 日
I want to store the values of f as shown below to make histogram. this way i am getting only the last iteration.
Any help
thank you
myFolder = p3;%
% Get a list of all files in the folder with the desired file name pattern.
file= fullfile(myFolder, '*.CSV'); % Change to whatever pattern you need.
Files = dir(file);
for k = 1 : length(Files)
FileName = Files(k).name;
fullFileName = fullfile(Files(k).folder, FileName);
l = readtable(fullFileName);
f=l{:,3};
end
histogram(f,4)

サインインしてコメントする。


Image Analyst
Image Analyst 2022 年 9 月 27 日
You need to index f. Actually I'd use more descriptive variable names. No one wants to look at code that looks like aphabet soup.
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(myFolder, '*.CSV'); % Change to whatever pattern you need.
fileList = dir(filePattern);
for k = 1 : length(fileList)
% Read in this table.
baseFileName = fileList(k).name;
fullFileName = fullfile(fileList(k).folder, baseFileName);
thisTable = readtable(fullFileName);
% Extract the third column only.
column3 = thisTable{:, 3};
% Append this column to our master vector.
if k == 1
allColumn3s = column3;
else
allColumn3s = [allColumn3s; column3]
end
end
numBins = 4;
histogram(allColumn3s, numBins)
grid on;
If you have any more questions, then attach your data (at least 2 CSV files) with the paperclip icon after you read this:
  3 件のコメント
Bizuayehu Addisie Beyene
Bizuayehu Addisie Beyene 2022 年 9 月 27 日
I already accepted your answer !
Havea good day :)

サインインしてコメントする。

カテゴリ

Find more on Large Files and Big Data in Help Center and File Exchange

タグ

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by