how to import csv file in matlab

10 403 vues (au cours des 30 derniers jours)
Nur Zakaria
Nur Zakaria le 18 Avr 2013
Commenté : Dyuman Joshi le 29 Déc 2023
Hi, I have one question. I need to import data into MATLAB from a CSV file. Unfortunately, the data has header information in 3 columns.
How do I skip the headers and get the data directly?
For example:
a= import data ('C:\s11.dat') *
Then what is the next step? I need your help.
Thank you.
  4 commentaires
Pratik
Pratik le 29 Déc 2023
Déplacé(e) : Dyuman Joshi le 29 Déc 2023
I have .csv, in which first column is in date format. second and third columns are integer values. how to read those columns and plot ?
Dyuman Joshi
Dyuman Joshi le 29 Déc 2023
Use readtimetable and specify the 1st column as the date-time data.

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Réponse acceptée

Mukesh Jadhav
Mukesh Jadhav le 9 Oct 2016
Modifié(e) : MathWorks Support Team le 15 Mar 2021
To import data from a CSV file into MATLAB use the “readtable” function. The “readtable” function automatically detects the header and the number of lines to skip.
T = readtable('myfile.csv');
Alternatively, you can specify the number of lines to skip using:
T = readtable('myfile.csv','NumHeaderLines',3); % skips the first three rows of data
For more information, see:
  2 commentaires
francisco caldeira
francisco caldeira le 4 Mai 2020
Modifié(e) : francisco caldeira le 4 Mai 2020
readtable('myfile.csv'); this generates a warning -> ' Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property. Set 'PreserveVariableNames' to true to use the original column headers as table variable names. '
To solve do:
T = readtable('myfile.csv','PreserveVariableNames',true);
Yongwon Jang
Yongwon Jang le 18 Juil 2023
In ver 2023a, syntex changed like below:
T = readtable('myfile.csv', 'VariableNamingRule', 'preserve');

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Plus de réponses (3)

Karen Hornsby
Karen Hornsby le 18 Avr 2013
HI, You can either use the import data wizard by right clicking on the file in the current folder window. When the import wizard opens it should give you a preview of the data and in the top right is a box which asks you how many header lines there are. You can use this to create code to open files of this type repeatedly (this works well but if your new to matlab it can be a bit confusing to edit) or you can used the following code to open files
ftoread = '%file name';
fid = fopen(ftoread);
fgetl(fid) %reads line but does nothing with it
fgetl(fid)
fgetl(fid)
M = textscan(fid, '%f', 'Delimiter','\,'); % you will need to change the number of values to match your file %f for numbers and %s for strings.
fclose (fid)
You can get more help with this in the help file, just type in the command you want help with in the search box. Karen

Thomas
Thomas le 18 Avr 2013
Modifié(e) : Thomas le 18 Avr 2013
I think the easiest way is to use CSVIMPORT from the File Exchange:
%read data example: Import columns as column vectors
[X Y Z] = csvimport('vectors.csv', 'columns', {'X, 'Y', 'Z'});
%remove headers
X(1) = [];
Y(1) = [];
Z(1) = [];
This assumes that the first element in the array contains the header
Thomas
  1 commentaire
Thomas Carter
Thomas Carter le 6 Juin 2022
Modifié(e) : Thomas Carter le 6 Juin 2022
I have found that with large datasets, csvimport corrupts data. Spent a full day trying to figure this one out.

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jgd0008
jgd0008 le 2 Déc 2016
Modifié(e) : per isakson le 2 Déc 2016
Hi, Something like this, may work;
data = fopen('file_name.csv');
A = textscan(data,'%s','Delimiter','\n');
B = A{1,1};
fclose(fid);
C = textscan(B,'%s','Delimiter',',');
D = C{1};

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