On 2014-01-10, Terry Reedy <tjre...@udel.edu> wrote: > On 1/10/2014 12:38 PM, Albert-Jan Roskam wrote: >> In Python Cookbook, one of the authors (I forgot who) consistently used the >> "L[:]" idiom like below. If the second line simply starts with "L =" (so no >> "[:]") only the name "L" would be rebound, not the underlying object. That >> was the author?? explanation as far as I can remember. I do not get that. >> Why is the "L[:]" idiom more memory-efficient here? How could the increased >> efficiency be demonstrated? >> >> #Python 2.7.3 (default, Sep 26 2013, 16:38:10) [GCC 4.7.2] on linux2 >>>>> L = [x ** 2 for x in range(10)] >>>>> L[:] = ["foo_" + str(x) for x in L] > > Unless L is aliased, this is silly code.
And if L _is_ aliaised, it's probably trying to be too clever and needs to be fixed. -- Grant -- https://mail.python.org/mailman/listinfo/python-list
