How to Use Logical Operator Within If Statements in MATLAB?

Logical Operators are used to combining two or more conditions/constraints or to complement the evaluation of the original condition in consideration. The result of the operation of a logical operator is a boolean value either true or false. Like any other programming language, logical operators in MATLAB are beneficial, and in this article, we will demonstrate one of its uses.

MATLAB logical operator and function: 

• Element-wise: These operators function on corresponding factors of logical arrays. Element-wise logical operators function detail-by-detail on logical arrays. The symbols &, |, and ~ are the logical array operators AND, OR, and NOT.
• Short-circuit: These operators function on scalar, logical expressions. Short-circuit logical operators permit short-circuiting on logical operations. The symbols && and || are the logical short-circuit operators AND and OR.

But before we learn how to use logical operators with conditional statements, we should have a quick look at logical operators.

• Logical AND(&): True if both the operands are true.

Operand1	Operand2	Operand1 & Operand2
True	True	True
True	False	False
False	True	False
False	False	False

• Logical OR( | ): True if either of the operands is true.

Operand1	Operand2	Operand1 | Operand2
True	True	True
True	False	True
False	True	True
False	False	False

• Logical XOR(xor): The result of XOR is true if the two bits are different.

Operand1	Operand2	Operand1 xor Operand2
True	True	False
False	True	True
True	False	True
False	False	False

• Logical NOT( ~ ): True if the operand is false.

Operand	~Operand
True	False
False	True

Now, here is a MATLAB example that illustrating logical operators with conditional statements.

Example 1:

Matlab

% MATLAB code for Logicl Operators
% in use, 1 - True,  0 - False
% logical and operator
andResult = 1 & 0;

% logical or operator
orResult = 1 | 0;

% logical xor operator
xorResult = xor(1,0);

% logical not operator
notResult = ~1;

% logical all()
allResult = all([1 2 3 4 5]);

% logical()
logicalResult = logical(76);

% islogical()
isLogicalResult = islogical([true false true]);

% logical find()
findResult = find([1 2 0 0 0 3 4 2]);

% logical any()
anyResult = any([1 0 2 3]);

disp("1 & 0 = " + andResult);
disp("1 | 0 = " + orResult);
disp("1 XOR 0 = " + xorResult);
disp("~1 = " + notResult);
disp("all([1 2 3 4 5]) = " + allResult);
disp("logical(87) = " + logicalResult);
disp("isLogical([true false true]) = " + isLogicalResult);
disp("find([1 2 0 0 0 3 4 2])");
findResult
disp("any([1 0 2 3]) = " + anyResult);

Output:

So now that we have a rudimentary understanding of the logical operator, we can use them in our conditional statements. Now we are going to use the logical operators in conditional statements.

Example 2:

Matlab

% MATLAB script is used to determine
% the nature of the product (positive,
% negative or zero) of  the two
% numbers given by the user
num1 = input('Enter the first number:- ');
num2 = input('Enter the second number:- ');

% here we are using && instead of & and ||
% instead of | because it makes the code
% execution faster as if the condition fails
% in the first operand the second operand is not tested
% If the both the numbers are greater that
% zero or both the numbers are less than zero
% their product will be positive
if((num1 > 0 && num2 > 0) || (num1 < 0 && num2 < 0))
disp('The product of the two numbers will be positive');

% If the numbers have opposite sign then
% their product will be negative
elseif((num1 > 0 && num2 < 0) || (num1 < 0 && num2 > 0))
disp('The product of the two numbers will be negative');
else
disp('The product of the two numbers will be zero');
end

Output:

The above MATLAB script outputs the nature of the product of the two numbers given by the user and, while doing so, also illustrates how to use logical operators in conditional statements(like the If statement) So, logical operators are convenient when working with conditional statements.

MATLAB functions for logical operations:

• all(): This determines if all array elements are nonzero or true. In this logical operation if all the elements of the array are non-zero then the output will be 1 (true) and If at least one of the elements is zero then the output will be 0 (false).
• logical(): This function converts the non-zero elements to 1 and the zero elements to 0.
• isLogical(): In this function If the input is logical i.e. true or false then the output will be 1, and if the input is anything apart from logical then the output will be 0.
• find(): Finds and returns the indices of non-zero elements in the array.
• any(): If any element in an array is non-zero the output is 1 if not then the output is 0.