Logical operators in python!

Logical operators are those operators which are used to combine two or more expressions and yield the results as either True or False.

not operator

This is a unary logical operator which requires only one operand.

      True => False
      False=> True

and operator

This is a binary logical operator which involves two operands.

     True    True   => True
     True    False  => False
     False   True   => False
     False   False  => False

or operator

This is a binary logical operator which involves two operands.

     True    True   => True
     True    False  => True
     False   True   => True
     False   False  => False

The above is also their order of precedence decreases from top to bottom i.e. not operator has highest precedence and the or operator has the lowest!

Short-circuit evaluation of boolean expression

While evaluating an expression that involves an and operator, the second sub-expression is evaluated only if the first sub-expression yields as True. If the first sub-expression yields False, then python does not evaluate the second sub-expression; thus determining the value of whole expression as False. This is called as short-circuit evaluation of boolean expression.

Similarly, While evaluating an expression that involves an or operator, the second sub-expression is evaluated only if the first sub-expression yields as False.

Now, the precedence of arithmetic, logical and relational operators in decreasing order is as follow.

 Arithmetic Operator
 Relational Operator
 Logical Operator

Hope you are following the notes.Stay tuned for more!