[Python] Check for None (Null) in Python


If you’ve used other programming languages, you may have learned that an empty object is not the same as an object that does not exist. In this lesson, you’ll learn how to check for None (or Null objects) in Python.

 

foo = None

if foo is None:
    print("is None")

if foo == None:
    print("also none")

 

Using 'is' can be better when check is None or not, because 'is' is doing id comparsion:

id(foo) == id(None)

It is much faster check '==' it does a deep looking for the value.


免责声明!

本站转载的文章为个人学习借鉴使用,本站对版权不负任何法律责任。如果侵犯了您的隐私权益,请联系本站邮箱yoyou2525@163.com删除。



 
粤ICP备18138465号  © 2018-2025 CODEPRJ.COM