Python Null or None Object
In python, the None keyword is use to define the Null value of an object or variable; it is an object and a NoneType data type.
Note:
- We can define None to any variable or object.
- None is not equal to 0
- None is not equal to FALSE
- None is not equal to empty string
- None is only equal to None
We can check None by keyword “is” and syntax “==”
Example:
# Python program to check None value
# initialized a variable with None value
myval = None
# Check by using 'is' keyword
if myval is None:
print('myval is None')
else:
print('myval is not None')
# Check by using '==' syntax
if myval == None:
print('myval is None')
else:
print('myval is not None')
Output:
myval is None
myval is None
Check None type
# Python program to check None value
# initialized a variable with None value
myval = None
print(type(myval))
Output:
<class 'NoneType'>
Check if None is equal to None
# Python program to check None value
# initialized a variable with None value
myval = None
if None is None:
print('None is None')
else:
print('None is Not None')
print(None == None)
Output:
None is None
True
Check if None is equal to False
Example:
# initialized a variable with None value
myval = None
if myval == False:
print('None is equal to False')
else:
print('None is Not Equal to False')
print(None == False)
Output:
None is Not Equal to False
False
Check if None is equal to empty string
# Inilised a variable with None value
myval = ''
if myval == None:
print('None is equal to empty string')
else:
print('None is Not Equal to empty string')
print(None == myval)
Output:
None is Not Equal to empty string
False
Return None or Null from function
# Python program to check None value
# Using custom function
# initialized a variable with None value
myval = None
# Define function
def nullfunction(myval):
# Check if variable is None
if myval is None:
result = None
else:
result = 'myval is not None'
return result
print('Output: ',nullfunction(myval))
Output:
Output: None
