The bool() function checks if a value is True or False, and returns the Boolean.
bool() on empty list
print(bool([]))
In this example we test an empty list, and boolean() returns False.
False
bool() on integer 0
print(bool(0))
In this example we test the integer 0, and boolean() returns False.
False
bool() on float 0.0
print(bool(0.0))
In this example we test the float 0.0, and boolean() returns False.
False
bool() on non-empty string
print(bool('test string'))
In this example we test a string, and boolean() returns True.
True
bool() on non-empty list
print(bool([0]))
In this example we test a non-empty list, and boolean() returns True.
True
bool on complex number
print(bool(0j))
In this example we test the complex number 0j, and boolean() returns False.
False
bool() on None
print(bool(None))
In this example we test None, and boolean returns False.
bool() syntax
The syntax of bool() is:
bool(value)
bool() arguments
The bool() function accepts at most 1 argument.
If more than one argument is passed, an TypeError exception is raised.
If no argument is passed, it returns False.
bool() return values
The bool() function returns True, if the value is considered True. And it returns False, if the value is considered False.
See this table for the most common return values:
| condition |
return value |
| True |
True |
| non-empty string |
True |
| non-zero integer |
True |
| non-zero float |
True |
| non-zero complex number |
True |
| non-empty list |
True |
| non-empty dictionary |
True |
| False |
False |
| None |
False |
| 0 |
False |
| 0.0 |
False |
| 0j |
False |
| () |
False |
| empty list [] |
False |
| empty string '' |
False |
| empty dictionary {} |
False |