Logical Operations in Matlab Programming

MATLAB provide two types of logical operators:

Element-wise − these operators operate/work on corresponding elements of logical arrays.
Short-circuit − these operators operate/work on scalar, logical expressions.

Element-wise logical operators operate by taking single element at a time of logical arrays. The symbols |, & and ~ are the logical array operators OR, AND, and NOT respectively.

Short-circuit logical operators do short-circuiting on logical operations. The symbols || and&& are the logical short-circuit operators OR and AND respectively.

These can be better understood by taking the following examples.

Example1.

a = 5;

b = 20;

if ( a && b )

disp('Line 1 - Condition is true');

end

if ( a || b )

disp('Line 2 - Condition is true');

end>

Example2.

% lets change in the value of a and b

a = 0;

b = 10;

if ( a && b )

disp('Line 3 - Condition is true');

else

disp('Line 3 - Condition is not true');

end

if (~(a && b))

disp('Line 4 - Condition is true');

end

MATLAB always gives the (& ) operator preference over the | operator. Although MATLAB generally evaluates expressions from left to right, the expression a|b&c is solved as a|(b&c). It may be a good idea to use brackets to explicitly show the intended precedence of statements containing combinations of & and |.

These logical operators have the M-file function equivalents, as shown.