On 09/07/2007 21.23, Walter Dörwald wrote:
> >>> from ll.xist import parsers, xfind
> >>> from ll.xist.ns import html
> >>> e = parsers.parseURL("http://www.python.org";, tidy=True)
> >>> print e.walknode(html.h2 & xfind.hasclass("news"))[-1]
> Google Adds Python Support to Google Calendar Developer's Guide
>
>
> Get the first comment line from a python file:
>
> >>> getitem((line for line in open("Lib/codecs.py") if
> line.startswith("#")), 0)
> '### Registry and builtin stateless codec functions\n'
>
>
> Create a new unused identifier:
>
> >>> def candidates(base):
> ... yield base
> ... for suffix in count(2):
> ... yield "%s%d" % (base, suffix)
> ...
> >>> usedids = set(("foo", "bar"))
> >>> getitem((i for i in candidates("foo") if i not in usedids), 0)
> 'foo2'
You keep posting examples where you call your getitem() function with "0" as
index, or -1.
getitem(it, 0) already exists and it's spelled it.next(). getitem(it, -1)
might be useful in fact, and it might be spelled last(it) (or it.last()). Then
one may want to add first() for simmetry, but that's it:
first(i for i in candidates("foo") if i not in usedids)
last(line for line in open("Lib/codecs.py") if line[0] == '#')
Are there real-world use cases for getitem(it, n) with n not in (0, -1)? I
share Raymond's feelings on this. And by the way, if you wonder, I have these
exact feelings as well for islice... :)
--
Giovanni Bajo
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