enhancing 'list'
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From: Steve Holden on 19 Jan 2010 15:52 samwyse wrote: > On Jan 18, 1:56 am, Terry Reedy <tjre...(a)udel.edu> wrote: >> On 1/17/2010 5:37 PM, samwyse wrote: >> >> >> >> >> >>> Consider this a wish list. I know I'm unlikely to get any of these in >>> time for for my birthday, but still I felt the need to toss it out and >>> see what happens. >>> Lately, I've slinging around a lot of lists, and there are some simple >>> things I'd like to do that just aren't there. >>> s.count(x[, cmp[, key]]) >>> - return number of i�s for which s[i] == x. 'cmp' specifies a custom >>> comparison function of two arguments, as in '.sort'. 'key' specifies >>> a custom key extraction function of one argument. >>> s.index(x[, i[, j[, cmp[, key]]]]) >>> - return smallest k such that s[k] == x and i<= k< j. 'cmp' and >>> 'key' are as above. >>> s.rindex(x[, i[, j[, cmp[, key]]]]) >>> - return largest k such that s[k] == x and i<= k< j. 'cmp' and >>> 'key' are as above. >>> There are two overlapping proposals here. One is to add the .rindex >>> method, which strings already have. The other is to extend the >>> optional arguments of .sort to all other methods that test for item >>> equality. >>> One last thing, the Python 2.6.2 spec says .count and .index only >>> apply to mutable sequence types. I see no reason why they >>> (and .rindex) couldn't also apply to immutable sequences (tuples, in >>> particular). >> In 3.x, tuple does have those methods, even though the doc is not clear >> (unless fixed by now). > > That's good to hear. Perhaps I should have tried them directyly, but > my 3.1 docs still echo the 2.x docs, which only show them for > immutable sequences. The tuple IS an immutable sequence. regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 PyCon is coming! Atlanta, Feb 2010 http://us.pycon.org/ Holden Web LLC http://www.holdenweb.com/ UPCOMING EVENTS: http://holdenweb.eventbrite.com/ |