How to Read CSV Files in MATLAB: Simple Guide

In MATLAB, you can read CSV files using the readtable function to get a table or csvread for numeric data. Use readtable('filename.csv') to load the CSV into a table for easy data handling.

Syntax

The main functions to read CSV files in MATLAB are:

• readtable(filename): Reads the CSV file into a table, which can hold mixed data types.
• csvread(filename): Reads numeric data from a CSV file into a matrix.
• readmatrix(filename): Reads numeric and text data into a matrix or array.

Use filename as a string with the CSV file path.

matlab

T = readtable('data.csv');
M = csvread('data.csv');
A = readmatrix('data.csv');

Example

This example shows how to read a CSV file named sample.csv into a table and display its contents.

matlab

filename = 'sample.csv';
% Create a sample CSV file
fid = fopen(filename, 'w');
fprintf(fid, 'Name,Age,Height\nAlice,30,5.5\nBob,25,6.0\nCarol,27,5.7\n');
fclose(fid);

% Read CSV into a table
T = readtable(filename);

% Display the table
disp(T);

Output

    Name     Age    Height
    _____    ___    ______

    'Alice'  30     5.5   
    'Bob'    25     6     
    'Carol'  27     5.7   

Common Pitfalls

Common mistakes when reading CSV files in MATLAB include:

• Using csvread on files with text headers causes errors because it expects only numbers.
• Not specifying the correct file path or filename leads to file not found errors.
• Ignoring mixed data types; csvread cannot handle text, so prefer readtable or readmatrix for mixed data.

Example of wrong and right usage:

matlab

% Wrong: Using csvread on CSV with headers
% M = csvread('sample.csv'); % This will error

% Right: Use readtable instead
T = readtable('sample.csv');

Quick Reference

Function	Description	Use Case
readtable(filename)	Reads CSV into a table	Best for mixed data types and headers
csvread(filename)	Reads numeric data only	Use for numeric-only CSV without headers
readmatrix(filename)	Reads numeric and text data	Flexible for mixed data, newer alternative

Key Takeaways

Use readtable to read CSV files with headers and mixed data types.

csvread works only for numeric data without headers and is less flexible.

Always check the file path and name to avoid file not found errors.

readmatrix is a modern alternative that handles mixed data well.

Creating a sample CSV file helps test your reading code quickly.