[Python-Dev] iterzip() (original) (raw)

Raymond Hettinger python@rcn.com
Sun, 28 Apr 2002 21:39:53 -0400

----- Original Message ----- From: "Barry A. Warsaw" <barry@zope.com> To: "Raymond Hettinger" <python@rcn.com> Cc: "Guido van Rossum" <guido@python.org>; <python-dev@python.org>

>>>>> "RH" == Raymond Hettinger <python@rcn.com> writes:

RH> IMHO, This is a better way to loop over multiple sequences and RH> has a chance at becoming the tool of choice. I scanned all of RH> my Python code and found that iterzip() was a better choice in RH> every case except a matrix transpose coded as zip(*mat). I'd much rather see a patch that just changed zip() to be an iterator instead of adding an iterzip(). I doubt that much in-field code would break because of it (but write the PEP to find out. ;).

I started down this road, by checking code in the Vaults of Parnassus on the assumption that zip() is rarely used outside a for-loop. What may be the killer is the examples of zip() in Python books which demonstrate a stand-alone zip() returning a list -- in some ways, textbook examples are just as important as in-field code.

I will write-up a PEP to see if the world cares. For all I know, I may be the only who uses zip() throughout my code. Zip is just new enough that it might not be too late to change it to an iterator.

RH> Ditto. Any chance of moving functions like map(), reduce(), RH> and filter() to a functional module; pow() and divmod() to the RH> math module; or input() to oblivion? >>>>> "GvR" == Guido van Rossum <guido@python.org> writes: GvR> I wish. Since they were there first, it's hard to get rid of GvR> them. (If you're truly masochist, write a PEP and post it to GvR> c.l.py to find out how hard. :-) The PEP would have to specify a migration plan, i.e. the builtins are identical to the functional module versions, and would a deprecation schedule, etc.

Will do. I think the resistance to moving the functionals will be fierce. Divmod probably has very few instances in real code. I think pow would need to be left in (as the ** that calls it), but the function itself may be used only rarely.

Does anyone know of an automated what that I can scan a large body of published Python code. I would want some real usage statistics in a PEP but hate pulling modules down one at a time and grepping them.

Raymond Hettinger

-Barry