5.3. Saving output to a file

In addition to displaying output on the screen, the command fprintf can be used for writing the output to a file. The saved data can subsequently be used by MATLAB or other softwares.

This chunk introduces the concept of saving output in MATLAB. Instead of just printing results on the screen, you can save them into a file using the fprintf function. This is helpful if you want to store results for later use, whether in MATLAB or in another software program.

Think of this like writing a report instead of just giving a verbal presentation. When you write a report, you can share your findings with others and refer back to them later.

To save the results of some computation to a file in a text format requires the following steps:

1. Open a file using fopen
2. Write the output using fprintf
3. Close the file using fclose

This chunk outlines the three essential steps for saving data in MATLAB:

1. Open a file: Use the fopen function to create or open a file where data will be saved.
2. Write output: Use the fprintf command to write your data into the opened file.
3. Close the file: Finally, use fclose to close the file and ensure all data is saved properly. This ensures you don't lose your data and the file is not left open accidentally.

Imagine you're typing a letter on your computer. First, you would open a new document, then write your letter, and finally, you'd save the document. If you just closed the document without saving, all your writing would be lost!

Here is an example (script) of its use.

% write some variable length strings to a file
op = fopen('weekdays.txt','wt');
fprintf(op,'Sunday\nMonday\nTuesday\nWednesday\n');
fprintf(op,'Thursday\nFriday\nSaturday\n');
fclose(op);

In this example, MATLAB code is provided to save the days of the week into a file named 'weekdays.txt'. The script first opens (or creates) the file in write mode ('wt') using fopen. It then writes each day of the week followed by a newline character ('\n') to ensure each day appears on a new line. Finally, it closes the file using fclose to save the changes made.

Think of this as jotting down the days of the week on a piece of paper. You start with 'Sunday', write it down, move to the next line, and continue until you've written all the days. Finally, you set the paper aside ensuring your writing is saved.

This file (weekdays.txt) can be opened with any program that can read .txt file.

Once the weekdays have been saved into 'weekdays.txt', you can open this file using any text editor or software that supports reading text files. This means you can access the saved data later and utilize it as needed, whether in another MATLAB script, or simply to view the contents.

When you write a letter and save it on your computer, you can open it later in any text editor to read or edit. Similarly, the file you created in MATLAB can be accessed at any time to check its contents.

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