[Python-ideas] pop multiple elements of a list at once

Brett Cannon brett at python.org
Sun Jul 11 20:47:53 CEST 2010

On Sun, Jul 11, 2010 at 10:58, Diego Jacobi <jacobidiego at gmail.com> wrote:
> Hi.
> As recommended here: http://bugs.python.org/issue9218
> I am posting this to this list.
> I am currently working with buffer in an USB device and pyusb.
> So when i read from the buffer of endpoint, i get an array.Array() list.
> I handle this chunk of data with a thread to send a receive the
> information that i need.
> In this thread, i load a list with all the information that is read
> from the USB device, and another layer with pop this information from
> the threads buffer.
> The thing i found is that, to pop a variable chunk of data from this
> buffer without copying it and deleting the elements, i have to pop one
> element at the time.
>    def get_chunk(self, size):
>        for x in range(size):
>            yield self.recv_buffer.pop()
> I guess that it would be improved if i can just pop a defined number
> of elements, like this:
> pop self.recv_buffer[:-size]
> or
> self.recv_buffer.pop(,-size)
> That would be... "pop from (the last element minus size) to (the last element)"
> in that way there is only one memory transaction.
> The new list (or maybe a tuple) points to the old memory address and
> the recv_buffer is advanced to a one new address. Data is not moved.

Why can't you do ``del self.recv_buffer[-size:]``?

> Note that i like the idea of using "pop" as the "del" operator for
> lists, but i am concient that this would not be backward compatible.

Too specialized, so that will never fly.


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