For loops in MATLAB

Introduction

For loops help you repeat a set of actions many times without writing the same code again and again.

When you want to add numbers from 1 to 10.

When you want to print each item in a list one by one.

When you want to perform the same calculation on many values.

When you want to create a pattern by repeating steps.

When you want to process rows in a table or matrix.

Syntax

MATLAB

for index = startValue:endValue
    % commands to repeat
end

The index changes from startValue to endValue, one step at a time.

The commands inside the loop run once for each value of index.

Examples

This prints numbers 1 to 5, one number per line.

MATLAB

for i = 1:5
    disp(i)
end

This counts down from 10 to 2 by steps of 2 and prints each number.

MATLAB

for x = 10:-2:2
    disp(x)
end

This prints each letter in the array one by one.

MATLAB

for letter = ['a', 'b', 'c']
    disp(letter)
end

Sample Program

This program adds numbers from 1 to 5 using a for loop and then prints the total.

MATLAB

sum = 0;
for n = 1:5
    sum = sum + n;
end
fprintf('Sum of numbers 1 to 5 is %d\n', sum);

Important Notes

Remember to end the loop with end in MATLAB.

You can use any variable name for the loop index, not just i.

The step size in the loop can be changed by adding a third number in the range, like 1:2:9.

Summary

For loops repeat commands for a set number of times.

The loop index changes each time to control repetition.

Use end to close the loop block.