[Python-ideas] Null coalescing operators

Chris Angelico rosuav at gmail.com
Wed Sep 23 00:53:00 CEST 2015


On Wed, Sep 23, 2015 at 4:22 AM, Sven R. Kunze <srkunze at mail.de> wrote:
> I can tell from what I've seen that people use None for: all kinds of
> various interesting semantics depending on the variable, on the supposed
> type and on the function such as:
>
> - +infinity for datetimes but only if it signifies the end of a timespan

What this means is that your boundaries can be a datetime or None,
where None means "no boundary at this end".

> - current datetime
> - mixing both

I don't know of a situation where None means "now"; can you give an example?

> - default item in a list like [1, 2, None, 4, 9] (putting in 5 would have
> done the trick)

What does this mean? Is this where you're taking an average or
somesuch, and pretending that the None doesn't exist? That seems
fairly consistent with SQL.

Mostly, this does still represent "no such value".

ChrisA


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