How to test a variable is null in python

Question

val       del val  if val is None      print  null     I ran above code  but got NameError  name  val  is not defined   How to decide whether a variable is null  and avoid NameError

User · Answer

try      if val is None    The variable         print  It is None   except NameError      print   This variable is not defined   else      print   It is defined and has a value

User · Answer

You can do this in a try and catch block   try      if val is None          print  null   except NameError        throw an exception or do something else

User · Answer

Testing for name pointing to None and name existing are two semantically different operations   To check if val is None   if val is None      pass    val exists and is None   To check if name exists   try      val except NameError      pass    val does not exist at all

[python] How to test a variable is null in python

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