how to import csv file in matlab
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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.
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Mukesh Jadhav
2024-11-13
编辑:MathWorks Support Team
2024-11-22
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: https://www.mathworks.com/help/matlab/ref/readtable.html
2 个评论
francisco caldeira
2020-5-4
编辑:francisco caldeira
2020-5-4
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
2023-7-18
In ver 2023a, syntex changed like below:
T = readtable('myfile.csv', 'VariableNamingRule', 'preserve');
更多回答(4 个)
Karen Hornsby
2013-4-18
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
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Thomas Seers
2013-4-18
编辑:Thomas Seers
2013-4-18
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
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Senam
2024-9-20
Please this did not work for me. My matlab could not recognise the csvimport command
jgd0008
2016-12-2
编辑:per isakson
2016-12-2
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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Aidil
2025-1-17
编辑:Walter Roberson
2025-1-17
To import data from a CSV file in MATLAB and skip the header rows, you can use the readtable, readmatrix, or csvread (deprecated) functions, depending on your needs. Here's how to handle the issue:
Steps to Import Data from a CSV File and Skip Headers1. Using readtable (Preferred Method)
The readtable function is highly flexible and works well with tabular data. You can specify the number of header lines to skip.
% Define the file path
filePath = 'C:\s11.dat';
% Read the data into a table, skipping the first 3 rows
dataTable = readtable(filePath, 'HeaderLines', 3);
% Access the data as a table
disp(dataTable);
% If you need the data as an array
dataArray = table2array(dataTable);
disp(dataArray);
2. Using readmatrix
If you just need numeric data, readmatrix is simpler and skips headers by default.
% Define the file path
filePath = 'C:\s11.dat';
% Read the matrix data (skips non-numeric headers automatically)
dataMatrix = readmatrix(filePath);
disp(dataMatrix);
3. Using textscan (For Custom Parsing)
If the file has a complex structure, you can use textscan to read and parse the data manually.
% Open the file
fileID = fopen('C:\s11.dat', 'r');
% Skip the first 3 lines (headers)
for i = 1:3
fgetl(fileID); % Read and discard the header lines
end
% Read the data (adjust format specifier based on your file's structure)
data = textscan(fileID, '%f %f %f', 'Delimiter', ',');
% Close the file
fclose(fileID);
% Combine data into a matrix if needed
dataMatrix = cell2mat(data);
disp(dataMatrix);
4. Using csvread (Deprecated)
While csvread has been replaced by readmatrix, you can still use it by specifying the row and column offset. For example:
% Define the file path
filePath = 'C:\s11.dat';
% Skip the first 3 rows (row index starts from 0)
dataMatrix = csvread(filePath, 3, 0);
disp(dataMatrix);
Best Practices
- Use readtable or readmatrix for newer MATLAB versions (R2019a and later).
- Ensure the file path is correct and the file is accessible.
- If the data contains non-numeric values, use readtable for flexibility.
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