3.1: Boolean Expressions
- Page ID
- 3023
A boolean expression is an expression that is either true or false. The following examples use the operator ==
, which compares two operands and produces True
if they are equal and False
otherwise:
>>> 5 == 5
True
>>> 5 == 6
False
{}
True
and False
are special values that belong to the class bool
; they are not strings:
>>> type(True)
<class 'bool'>
>>> type(False)
<class 'bool'>
The ==
operator is one of the comparison operators; the others are:
x != y # x is not equal to y
x > y # x is greater than y
x < y # x is less than y
x >= y # x is greater than or equal to y
x <= y # x is less than or equal to y
x is y # x is the same as y
x is not y # x is not the same as y
Although these operations are probably familiar to you, the Python symbols are different from the mathematical symbols for the same operations. A common error is to use a single equal sign (=
) instead of a double equal sign (==
). Remember that =
is an assignment operator and ==
is a comparison operator. There is no such thing as =<
or =>
.