MATLAB Output Guide: Displaying Results for Beginners

MATLAB is a powerful tool for technical computing and data analysis, but sometimes the displayed results may not be exactly as you want them. So, how do you effectively and clearly display results in MATLAB? Let’s explore some simple yet effective secrets in this article!

1. Understanding How MATLAB Displays Results

Before diving into techniques for displaying results, we need to understand the basics of how MATLAB shows output. MATLAB usually displays results in the “Command Window”. When you execute a command, the result is shown in the last line of this window.

For example, if you enter 2+2 and press Enter, MATLAB will display the result as ans = 4. ans is the default variable MATLAB uses to store the result of the last command.

2. Using the disp Command

The disp command is a basic tool for displaying results in MATLAB. It allows you to show any value, string, or calculation result in the Command Window.

Example:

>> a = 5;
>> b = 10;
>> disp(a + b);

Result:

15

The disp command will display the value of a + b (15) in the Command Window.

3. Using the fprintf Command

The fprintf command allows you to format the displayed results as you wish. It’s similar to the printf command in the C programming language.

Syntax:

fprintf(formatSpec, A1, A2, ...)

Where:

• formatSpec: The format string, which defines how the results are displayed.
• A1, A2, ...: The values or variables to be displayed.

Example:

>> a = 5;
>> b = 10;
>> fprintf('The sum of %d and %d is %dn', a, b, a + b);

Result:

The sum of 5 and 10 is 15

The fprintf command allows you to format results by adding text to the display string and using special characters to format numerical values (%d, %f, %e…).

4. Using the sprintf Command

The sprintf command is similar to fprintf, but instead of displaying results directly, it returns a string containing the formatted result.

Syntax:

str = sprintf(formatSpec, A1, A2, ...)

Where:

• formatSpec: The format string, which defines how the results are displayed.
• A1, A2, ...: The values or variables to be displayed.
• str: The variable containing the formatted result string.

Example:

>> a = 5;
>> b = 10;
>> str = sprintf('The sum of %d and %d is %dn', a, b, a + b);
>> disp(str);

Result:

The sum of 5 and 10 is 15

The sprintf command helps you create formatted result strings for use in other MATLAB functions.

5. Using the format Command

The format command allows you to change the default display format of MATLAB results.

Example:

>> format short
>> a = pi;
>> disp(a);

Result:

3.1416

>> format long
>> a = pi;
>> disp(a);

Result:

3.141592653589793

The format command allows you to adjust the precision of displayed results, for example: format short (displays 4 decimal digits), format long (displays 15 decimal digits), format long e (displays in scientific notation).

6. Displaying Results as Tables

To display results as tables, you can use the table or array2table commands.

>> data = [1 2 3; 4 5 6];
>> T = array2table(data);
>> disp(T);

Result:

    Var1    Var2    Var3
    ____    ____    ____
    1       2       3
    4       5       6

The array2table command converts the data array into a table T, and the disp command displays table T in the Command Window.

7. Saving Results to a File

To save results to a file, you can use the save command.

Example:

>> a = 5;
>> b = 10;
>> c = a + b;
>> save('results.mat', 'a', 'b', 'c');

The save command will save the values of variables a, b, c to the file results.mat. This file can be opened and used in other MATLAB sessions.

8. Exporting Results to a Text File

To export results to a text file, you can use the fprintf command with a file argument.

Example:

>> a = 5;
>> b = 10;
>> fid = fopen('results.txt', 'w');
>> fprintf(fid, 'The sum of %d and %d is %dn', a, b, a + b);
>> fclose(fid);

The fopen command opens the file results.txt in write mode ('w'). The fprintf command writes the result to the results.txt file. The fclose command closes the results.txt file.

9. Using Charts to Display Results

MATLAB provides many different types of charts to display results visually.

Example:

>> x = 1:10;
>> y = x.^2;
>> plot(x, y);

The plot command creates a line graph showing the relationship between x and y. MATLAB offers many other chart types such as bar, hist, scatter, pie…

10. Advanced Tips

• Use sprintf to create complex format strings.
• Use formatSpec in fprintf to control the precision of results.
• Combine fprintf and sprintf to create complex text files.
• Use the figure and subplot commands to create multi-panel plots.
• Use the title, xlabel, ylabel, legend functions to add information to plots.

FAQ

Q: How to display results as fractions?

A: You can use the rats command to convert decimal results to fractional form.

Q: How to print results to the console?

A: You can use the disp or fprintf commands to display results in the Command Window.

Q: How to write results to an Excel file?

A: You can use the xlswrite command to write results to an Excel file.

Q: How to create a data table from results?

A: You can use the table or array2table commands to convert data arrays into tables.

Q: How to create a histogram plot?

A: You can use the hist command to create a histogram plot.

Conclusion

Knowing how to display results in MATLAB is an important skill for effectively presenting and analyzing data. By using the commands and techniques introduced in this article, you can easily control how results are displayed, create beautiful tables and charts, and store results scientifically.

Note:

• This article only provides some basic tips. MATLAB has many advanced functions that allow you to customize how results are displayed in many different ways.
• Experiment with different commands and techniques to find the method that best suits your needs.
• Please contact us if you need further assistance with displaying results in MATLAB.