Re: dropwhile question
Thanks for the explanations. Regards, Raj On Sat, Aug 23, 2008 at 3:41 PM, Scott David Daniels [EMAIL PROTECTED] wrote: Rajanikanth Jammalamadaka wrote: list(itertools.dropwhile(lambda x: x5,range(10))) [5, 6, 7, 8, 9] Why doesn't this work? list(itertools.dropwhile(lambda x: 2x5,range(10))) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] Because it drops _while_ the condition is True (which it is for the first 0 entries in the sequence). What you want is: list(x for x in range(10) if 2 x 5) Note that: list(itertools.dropwhile(lambda x: x5, range(10)+range(10))) is [5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9], not [5, 6, 7, 8, 9, 5, 6, 7, 8, 9]. --Scott David Daniels Scott.Daniels.Acm.Org -- http://mail.python.org/mailman/listinfo/python-list -- For him who has conquered the mind, the mind is the best of friends; but for one who has failed to do so, his very mind will be the greatest enemy. Rajanikanth -- http://mail.python.org/mailman/listinfo/python-list
dropwhile question
list(itertools.dropwhile(lambda x: x5,range(10))) [5, 6, 7, 8, 9] Why doesn't this work? list(itertools.dropwhile(lambda x: 2x5,range(10))) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] Thanks, Raj -- For him who has conquered the mind, the mind is the best of friends; but for one who has failed to do so, his very mind will be the greatest enemy. Rajanikanth -- http://mail.python.org/mailman/listinfo/python-list
Re: dropwhile question
On Sat, 23 Aug 2008 14:54:09 -0700, Rajanikanth Jammalamadaka wrote: list(itertools.dropwhile(lambda x: x5,range(10))) [5, 6, 7, 8, 9] Why doesn't this work? list(itertools.dropwhile(lambda x: 2x5,range(10))) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] It *does* work. `dropwhile()` drops as long as the callable returns a true value and then it stops dropping. First value is 0 and ``2 0 5`` is `False` so nothing is dropped. What have you expected? Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: dropwhile question
Rajanikanth Jammalamadaka wrote: list(itertools.dropwhile(lambda x: x5,range(10))) [5, 6, 7, 8, 9] Why doesn't this work? list(itertools.dropwhile(lambda x: 2x5,range(10))) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] it works exactly as specified: help(itertools.dropwhile) Help on class dropwhile in module itertools: class dropwhile(__builtin__.object) | dropwhile(predicate, iterable) -- dropwhile object | | Drop items from the iterable while predicate(item) is true. | Afterwards, return every element until the iterable is exhausted. 205 False maybe you meant to use itertools.ifilter? help(itertools.ifilter) Help on class ifilter in module itertools: class ifilter(__builtin__.object) | ifilter(function or None, sequence) -- ifilter object | | Return those items of sequence for which function(item) is true. | If function is None, return the items that are true. list(itertools.ifilter(lambda x: x5,range(10))) [0, 1, 2, 3, 4] list(itertools.ifilter(lambda x: 2x5,range(10))) [3, 4] /F -- http://mail.python.org/mailman/listinfo/python-list
Re: dropwhile question
Fredrik Lundh wrote: maybe you meant to use itertools.ifilter? help(itertools.ifilter) Help on class ifilter in module itertools: class ifilter(__builtin__.object) | ifilter(function or None, sequence) -- ifilter object | | Return those items of sequence for which function(item) is true. | If function is None, return the items that are true. list(itertools.ifilter(lambda x: x5,range(10))) [0, 1, 2, 3, 4] list(itertools.ifilter(lambda x: 2x5,range(10))) [3, 4] or, more likely, ifilterfalse: list(itertools.ifilterfalse(lambda x: x5,range(10))) [5, 6, 7, 8, 9] list(itertools.ifilterfalse(lambda x: 2x5,range(10))) [0, 1, 2, 5, 6, 7, 8, 9] /F -- http://mail.python.org/mailman/listinfo/python-list
Re: dropwhile question
Rajanikanth Jammalamadaka wrote: list(itertools.dropwhile(lambda x: x5,range(10))) [5, 6, 7, 8, 9] Why doesn't this work? list(itertools.dropwhile(lambda x: 2x5,range(10))) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] Because it drops _while_ the condition is True (which it is for the first 0 entries in the sequence). What you want is: list(x for x in range(10) if 2 x 5) Note that: list(itertools.dropwhile(lambda x: x5, range(10)+range(10))) is [5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9], not [5, 6, 7, 8, 9, 5, 6, 7, 8, 9]. --Scott David Daniels Scott.Daniels.Acm.Org -- http://mail.python.org/mailman/listinfo/python-list
