MATLAB Programming

Logical Types
How Logical Arrays Are Used
MATLAB has two primary uses for logical arrays:
• “Using Logicals in Conditional Statements” on page 2-35
• “Using Logicals in Array Indexing” on page 2-35
Most mathematics operations are not supported on logical values.
Using Logicals in Conditional Statements
Conditional statements are useful when you want to execute a block of code
only when a certain condition is met. For example, the sprintf command
shown below is valid only if str is a nonempty string. The statement
if ~isempty(str) && ischar(str)
checks for this condition and allows the sprintf to execute only if it is true:
str = 'Hello';
if ~isempty(str) && ischar(str)
sprintf('Input string is ''%s''', str)
end
ans =
Input string is 'Hello'
Using Logicals in Array Indexing
MATLAB supports a type of array indexing that uses one array as the index
into another array. For example, array B below indexes into elements 1, 3, 6,
7, and10 of array A:
A = 5:5:50
A =
5 10 15 20 25 30 35 40 45 50
B = [1 3 6 7 10];
2-35