Tim Peters writes:
> But hasn't it already been settled by experience? There is nothing
> unique about `first(set)` implicitly appealing to iteration order.
I'm not sure. I wouldn't think to use "first" on a set in my own code
(and in others' code I'd consider it a code smell in many contexts,
such as the example below). I rarely think of the order involved in
iteration: I think of "for" as "for each". My focus is on a set of
objects and what I do with each, not necessarily limited by the von
Neumann architecture.
I'm also bothered that "first(x); first(x)" has "first, second"
semantics when x is an iterator and "first, first" semantics when x is
not an iterator. I'd like to be able to generically recommend
column_labels = first(table)
for row in table:
process(row, column_labels)
because it's very elegant, but it's probably a bug if table is a list
of tuples rather than an open file object. For me any use of "first"
that doesn't throw away the rest of the iterable would be suspect,
because changing a sequence to an iterator or the other way around is
a frequent refactoring for me. It's still elegant if used
carefully:
itable = iter(table)
column_labels = first(itable)
for row in itable:
process(row, column_labels)
but then "first" is just a slightly inefficient way of spelling next.
> I just don't see the potential for "new" bafflement if itertools.first
> works exactly the same way as itertools.anything_else _has_ worked, in
> this respect, all along.
Perhaps not. While I don't really trust a vote of the posters to this
list on issues of potential for bafflement ;-), the fact that nobody
else seems concerned is, uh, "suggestive".
> Give users some credit.
I'm happy to do that at 21.6% per annum, but wouldn't it be more
Pythonic to cut them some slack and keep them out of debt?
Steve
_______________________________________________
Python-ideas mailing list -- [email protected]
To unsubscribe send an email to [email protected]
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at
https://mail.python.org/archives/list/[email protected]/message/K2OMA4PD4O6EYP3TPIZZPVQ6KX2YQWXB/
Code of Conduct: http://python.org/psf/codeofconduct/
