[Python-Dev] python 3 niggle: None < 1 raises TypeError

[M.-A. Lemburg]

On 17.02.2014 13:19, Serhiy Storchaka wrote:
> 17.02.14 13:56, M.-A. Lemburg написав(ла):
>> Yes, but that's not the point. Unlike strings or other mixed types that
>> you cannot compare, None is used as placeholder in data processing as
>> special value to mean "no value available".
> 
> Isn't float('nan') such placeholder?

You can easily construct other such placeholders, but None was intended
for this purpose:

http://docs.python.org/2.7/c-api/none.html?highlight=none#Py_None

"""
The Python None object, denoting lack of value. ...
"""

>> You intentionally use such values in programming. It's not a bug to
>> have None in a data list or as value of a variable.
> 
> You can't have None in array('f'), you can't add or multiply by None. Relation operators don't looks
> an exception here. Applying sorted() to a list which contains numbers and Nones makes as much sense
> as applying sum() to it.

Of course, you cannot apply any operations with None - it doesn't
have a value -, but you can compare it to other objects and it provides
a consistent behavior in Python 2. Python 3 is missing such an object.

-- 
Marc-Andre Lemburg
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