Python True Keyword
In Python, True
is a built-in Boolean keyword that represents the truth value of expressions. It is often used in conditional statements, loops, and logical operations.
Syntax
True
Characteristics
Property | Description |
---|---|
Type | Boolean |
Value | Represents logical truth (1 in numeric operations). |
Usage | Used in conditional expressions, loops, and logical operations. |
Immutability | Cannot be modified as it is a constant keyword. |
Return Value
When used in expressions, True
evaluates to 1
in numeric operations and acts as a truthy value in logical conditions.
Examples
1. Using True in Conditional Statements
In this example, we use True
in an if
statement to control the flow of execution.
Here, the if
statement checks whether the condition is True
. Since True
always evaluates to a truthy value, the block of code inside the if
statement runs.
# Using True in an if statement
if True:
print("This condition is always True!")
Output:
This condition is always True!
Since True
is always considered as a truthy value, the print statement inside the if
block is executed.
2. True as a Boolean Expression
Boolean expressions return either True
or False
. Here, we evaluate simple conditions.
In the example below, we compare two numbers using a relational operator. If the comparison is correct, it returns True
.
# Boolean comparison
result = 10 > 5
print(result) # Output: True
Output:
True
Here, 10 > 5
is a logical expression that evaluates to True
, and the value is stored in the variable result
.
3. True in Logical Operations
Logical operations such as and
, or
, and not
use True
to determine the outcome.
In the following example, we combine Boolean values with logical operators to see how they interact.
# Using True in logical expressions
print(True and False) # Output: False
print(True or False) # Output: True
print(not True) # Output: False
Output:
False
True
False
In the first case, True and False
results in False
because both values must be True
for the and
operator to return True
. In the second case, True or False
results in True
because at least one value is True
. The not
operator inverts True
to False
.
4. True in Numeric Operations
Since True
is equivalent to 1
in Python, it can be used in arithmetic calculations.
In the example below, we use True
in mathematical expressions, and Python treats it as 1
.
# True in arithmetic operations
print(True + 2) # Output: 3
print(True * 5) # Output: 5
Output:
3
5
Here, True + 2
is equivalent to 1 + 2
, which results in 3
. Similarly, True * 5
is the same as 1 * 5
, giving 5
.
5. Mistakenly Assigning True as a Variable
Since True
is a built-in keyword, assigning a new value to it results in an error.
# Attempting to assign a value to True
try:
True = 5 # This will cause an error
except SyntaxError as e:
print("Error:", e)
Output:
SyntaxError: cannot assign to True
Python does not allow modifying built-in keywords. Attempting to do so results in a SyntaxError
.