How to Use save in MATLAB: Syntax and Examples

In MATLAB, use the save command to store workspace variables to a file. You can save all variables or specify which ones to save by name, and choose the file format like .mat or ASCII text.

Syntax

The basic syntax of save in MATLAB is:

• save filename: Saves all workspace variables to filename.mat.
• save filename var1 var2: Saves only specified variables var1 and var2.
• save filename -ascii: Saves variables in ASCII text format.
• save(filename, 'var1', 'var2'): Alternative function syntax to save specific variables.

matlab

save filename
save filename var1 var2
save filename -ascii
save(filename, 'var1', 'var2')

Example

This example shows how to save all variables and how to save selected variables to a file.

matlab

a = 10;
b = rand(3);
c = 'hello';
save('myData.mat'); % saves all variables
clear a b c
load('myData.mat') % loads all variables back

save('selectedData.mat', 'a', 'c') % saves only a and c
clear a c
load('selectedData.mat') % loads only a and c

Output

a = 10
b = [3x3 double matrix]
c = 'hello'

After loading selectedData.mat:
a = 10
c = 'hello'

Common Pitfalls

Common mistakes when using save include:

• Forgetting to specify variable names when you want to save only some variables, which saves everything by default.
• Using save filename without quotes can cause errors if the filename has spaces or special characters.
• Saving variables in ASCII format with -ascii only works for numeric data, not strings or complex types.

matlab

 % Wrong: saves all variables unintentionally
save myFile

 % Right: save only needed variables
save('myFile.mat', 'var1', 'var2')

Quick Reference

Command	Description
save filename	Save all workspace variables to filename.mat
save filename var1 var2	Save only var1 and var2 to filename.mat
save filename -ascii	Save variables in ASCII text format (numeric only)
save(filename, 'var1', 'var2')	Function syntax to save specific variables
load filename	Load variables from filename.mat back into workspace

Key Takeaways

Use save filename to save all workspace variables to a .mat file.

Specify variable names to save only selected variables and reduce file size.

Use quotes around filenames to avoid errors with spaces or special characters.

The -ascii option saves numeric data as text but cannot save strings.

Always check saved files by loading them back with load.