[Python-Dev] Shorthand for lambda
jcarlson at uci.edu
Wed Mar 23 22:26:44 CET 2005
Ka-Ping Yee <python-dev at zesty.ca> wrote:
> On Wed, 23 Mar 2005, Josiah Carlson wrote:
> > Paul Moore <p.f.moore at gmail.com> wrote:
> > > I thought about it, but couldn't convince myself that it would work
> > > properly in all cases. I was thinking in terms of operator overloading
> > > of everything possible - how did you do it?
> > PyTables allows something very similar for "in-kernel" searches of data,
> > but only on a single constraint. I would imagine that Ka-Ping did it by
> > only allowing a single operation per item.
> You can do more than one operation, but the usage is still quite limited.
> The item placeholder must be the first operand for it to work.
> >>> numbers = [3, 8, 4, 1, 2]
> >>> filter(_ < 5, numbers)
> [3, 4, 1, 2]
> >>> map(_ * 5 + 7, numbers)
> [10, 15, 11, 8, 9]
Your implementation "works" by not crashing, but that last map should
certainly return [22, 47, 27, 12, 17] rather than what it does.
It may be extensible to actually work the way I expect such operations
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