Writing Data to File in MATLAB

💾 Writing Data to File in MATLAB

MATLAB is developed by MathWorks.

🔹 Why Write Data to Files?

• Save computation results

• Share data with Excel/other tools

• Create logs and reports

• Preserve MATLAB variables (.mat)

1️⃣ Write Numeric Data to TXT/CSV — writematrix()

Best for numeric arrays.

🔸 Example

📌 For CSV:

Result: File created with matrix values.

2️⃣ Write Data to Excel — writematrix()

📌 Writes to the first sheet by default.

3️⃣ Write Tables (Mixed Data) — writetable()

Best when you have headers + mixed types.

Result: CSV with column headers.

4️⃣ Write Cell Arrays — writecell()

Useful for text + numbers without table semantics.

5️⃣ Write Text Files (Formatted) — fprintf()

Gives full control over formatting.

Result (report.txt)

6️⃣ Append Data to Existing File

7️⃣ Save MATLAB Variables — save()

Creates MATLAB’s native .mat file.

📌 Load later with:

8️⃣ Specify Delimiters & Options

⚠️ Important Notes

• writematrix() → numeric arrays

• writetable() → tables with headers

• writecell() → mixed cell data

• fprintf() → custom formatting

• Files are saved in the current folder unless a path is given

🎯 Interview Questions: Writing Data to File in MATLAB

🔹 Q1. Which function writes numeric data to a file?

Answer: writematrix()

🔹 Q2. How do you write mixed data with headers?

Answer: Using writetable().

🔹 Q3. Which function provides formatted output?

Answer: fprintf().

🔹 Q4. How do you save MATLAB variables?

Answer: Using save() to create a .mat file.

🔹 Q5. How do you append data to a file?

Answer: Open file with fopen(...,'a').

🔹 Q6. Difference between writematrix() and writecell()?

Answer:
writematrix() → numeric only
writecell() → text + numbers

✅ Summary

• MATLAB supports writing to TXT, CSV, Excel, MAT

• Choose function based on data type

• save() is best for MATLAB-only storage

• Essential for reporting and data exchange