Null in python?

Question

What is the equivalent of "null" in python to clean the column in calculate field?
I try use "None" ,but without any effect.

ThaiTruong · Answer

check out this blog for dealing with null values  when using field calculator:
http://blogs.esri.com/esri/arcgis/2010/08/30/concatenate/
# Special case for null soiltype
if soil == '':
    return veg

Basically, you need to convert the value into string even if it's already a string.

WilliamIde · Answer

Null What?

None should work for Null pointers

thing is an object.
if  thing == None :

thing is a string
one thing about strings however is users sometimes put man blank charagers in a string. So it looks empty  but "" will fail.  So you need to check thing.len() == 0 first.
if thing == "":

ChrisBater · Answer

None should not be in quotes.