[Python-Dev] Re: PEP 279
James Althoff
jamescalthoff@yahoo.com
Thu, 4 Apr 2002 11:33:13 -0800
Trying again without all the nasty HTML -- apologies to all.
[David Abrahams]
> . . . I want to put in another plug for itemize(),
Well, since we're doing post-Pronouncement fantasizing . . .
here's one more plug for "itemize".
Noting that
for k,v in adict.iteritems():
is probably as useful as
for i,v in enumerate(aseq):
why not change the spec to:
>>> def itemize(iterable):
... # use iteritems if defined
... try:
... for item in iterable.iteritems(): yield item
... except AttributeError: pass
... # and then everything as before
... i = 0
... iterator = iter(iterable)
... while 1:
... yield i,iterator.next()
... i += 1
...
So "itemize(iterable)" returns an iterator that yields (k,v) pairs from the
iterable.iteritems() method if defined, else pairs generated by associating
0,1,...,n-1 with n values from iter(iterable).
This allows
for k,v in itemize(adict_or_aseq):
to be written uniformly for dicts and seqs.
And makes
list(itemize(adict)) == adict.items()
work, removing one of the objections to the name "itemize".
Also, if one were to need, for example, a sequence whose indices start at 1
instead of 0, one could define a sequence class that implements iteritems
and objects of said class would work just fine with "itemize".
Jim