The not
keyword in Python is a logical operator used to negate a condition. It inverts the boolean value of a condition: if a condition evaluates to True
, not
will make it False
, and if it evaluates to False
, not
will make it True
. This operator is essential for expressing conditions that require the opposite of a given boolean value.
not
Keyword WorksThe not
operator is used to reverse the truth value of a condition.
In this example, is_sunny
is False
, so not is_sunny
evaluates to True
, and the if
block is executed.
not
in Conditional StatementsThe not
keyword is commonly used in if
statements and other control flow constructs to check the negation of a condition.
Here, since logged_in
is False
, not logged_in
evaluates to True
, prompting the message to be printed.
In this case, temperature > 30
is False
, and is_raining
is True
. The or
condition evaluates to True
, so not (True)
results in False
, leading to the else
block being executed.
This example checks if user_input
is empty. Since an empty string is considered False
in Python, not user_input
evaluates to True
, triggering the error message.
**None**
ValuesIn this scenario, data
is None
, which evaluates to False
. Therefore, not data
evaluates to True
, and the message is printed.
The not
keyword in Python is used to invert the truth value of a condition. It is a fundamental operator for negating boolean expressions and is widely used in control flow and logical operations. By understanding how not
works in conjunction with other logical operators, you can effectively manage conditions and make your Python code more expressive and flexible.