[Python-Dev] New PEP (original) (raw)

Ethan Furman ethan at stoneleaf.us
Thu Mar 22 01:09:22 CET 2012

Huan Do wrote:

*Hi,

I am a graduating Berkeley student that loves python and would like to propose an enhancement to python. My proposal introduces a concept of slicing generator. For instance, if one does x[:] it returns a list which is a copy of x. Sometimes programmers would want to iterate over a slice of x, but they do not like the overhead of constructing another list. Instead we can create a similar operator that returns a generator. My proposed syntax is x(:). The programmers are of course able to set lower, upper, and step size like the following. x(1::-1)

The biggest problem with your proposal is that generators don't remember what they have already yielded, so

x(:) != x(:) # first time gets everything, second time gets nothing

Ethan

More information about the Python-Dev mailing list