Writing text files (writetable, fprintf) in MATLAB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the writetable function do in MATLAB?

The writetable function saves a table variable to a text file, such as a CSV or TXT file, making it easy to export structured data.

beginner

How do you use fprintf to write formatted text to a file in MATLAB?

You first open a file with fopen, then use fprintf with a file identifier and a format string to write text, and finally close the file with fclose.

beginner

What is the purpose of the format specifier in fprintf?

The format specifier tells MATLAB how to display the data (like %d for integers, %f for floating-point numbers, %s for strings), controlling the output style.

beginner

Why should you always use fclose after writing to a file?

Closing the file with fclose ensures all data is saved properly and frees system resources, preventing file corruption or access issues.

intermediate

Can writetable write files other than CSV? Give an example.

Yes, writetable can write text files like tab-delimited TXT files by specifying the delimiter option, e.g., writetable(T, 'file.txt', 'Delimiter', '\t').

Which MATLAB function is best for writing a table directly to a CSV file?

A writetable

B fprintf

C fopen

D load

writetable is designed to save tables directly to files like CSV.

What must you do before using fprintf to write to a file?

A Use <code>load</code> first

B Close the file with <code>fclose</code>

C Convert data to string

D Open the file with <code>fopen</code>

You must open the file with fopen to get a file ID for fprintf.

What does the format specifier %f mean in fprintf?

A Floating-point number

B Integer

C String

D Character

%f formats numbers as floating-point values.

What happens if you forget to call fclose after writing a file?

A Nothing happens

B File deletes automatically

C Data might not be saved properly

D MATLAB crashes

Not closing the file can cause data loss or file corruption.

Which option allows writetable to write tab-delimited files?

A 'Format', '%s'

B 'Delimiter', '\t'

C 'Mode', 'append'

D 'Encoding', 'UTF-8'

Setting 'Delimiter', '\t' writes tab-separated values.

Explain the steps to write a matrix of numbers to a text file using fprintf in MATLAB.

Think about opening, writing with formatting, and closing.

Describe how writetable simplifies saving data compared to fprintf.

Focus on ease and automation.