Re: dropwhile question

[Fredrik Lundh]

Rajanikanth Jammalamadaka wrote:

>>>list(itertools.dropwhile(lambda x: x<5,range(10)))

[5, 6, 7, 8, 9]

Why doesn't this work?

>>>list(itertools.dropwhile(lambda x: 2<x<5,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.

>>2<0<5

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: x<5,range(10)))

[0, 1, 2, 3, 4]

>>list(itertools.ifilter(lambda x: 2<x<5,range(10)))

[3, 4]

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