[Python-ideas] Null coalescing operator

Zachary Ware zachary.ware+pyideas at gmail.com
Fri Sep 9 16:06:37 EDT 2016


On Fri, Sep 9, 2016 at 3:01 PM, Arek Bulski <arek.bulski at gmail.com> wrote:
> Sometimes I find myself in need of this nice operator that I used back in
> the days when I was programming in .NET, essentially an expression
>
>>>> expr ?? instead
>
> should return expr when it `is not None` and `instead` otherwise.
>
> A piece of code that I just wrote, you can see a use case:
>
>     def _sizeof(self, context):
>         if self.totalsizeof is not None:
>             return self.totalsizeof
>         else:
>             raise SizeofError("cannot calculate size")
>
> With the oprator it would just be
>
>     def _sizeof(self, context):
>         return self.totalsizeof ?? raise SizeofError("cannot calculate
> size")

This was proposed almost exactly a year ago, start reading here:
https://mail.python.org/pipermail/python-ideas/2015-September/036289.html

-- 
Zach


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