Terry Reedy [EMAIL PROTECTED] writes:
| I don't see what's so inefficient about it necessarily.
The key function is called once per list item, for n calls total. The
comparision function is called once per comparision. There are at least
n-1 such calls and typically something on the
Paul Rubin http://phr.cx@NOSPAM.invalid wrote in message
news:[EMAIL PROTECTED]
| Terry Reedy [EMAIL PROTECTED] writes:
| | I don't see what's so inefficient about it necessarily.
|
| The key function is called once per list item, for n calls total. The
| comparision function is called once
Paul Rubin http://[EMAIL PROTECTED] wrote:
Terry Reedy [EMAIL PROTECTED] writes:
| I don't see what's so inefficient about it necessarily.
The key function is called once per list item, for n calls total.
The comparision function is called once per comparision. There are
at least n-1
Dan Bishop wrote:
def cmp_key(cmp_fn):
class CmpWrapper(object):
def __init__(self, obj):
self.obj = obj
def __cmp__(self, other):
return cmp_fn(self.obj, other.obj)
return CmpWrapper
Apparently I'm overlooking something obvious ...
On Mar 13, 12:38 pm, Alan Isaac [EMAIL PROTECTED] wrote:
Dan Bishop wrote:
def cmp_key(cmp_fn):
class CmpWrapper(object):
def __init__(self, obj):
self.obj = obj
def __cmp__(self, other):
return cmp_fn(self.obj, other.obj)
return
Dan Bishop wrote:
def cmp_key(cmp_fn):
class CmpWrapper(object):
def __init__(self, obj):
self.obj = obj
def __cmp__(self, other):
return cmp_fn(self.obj, other.obj)
return CmpWrapper
On Mar 13, 12:38 pm, Alan Isaac wrote:
how is
On Mar 13, 3:48 pm, Alan Isaac [EMAIL PROTECTED] wrote:
So maybe this is not as bad as I feared. What are some use
cases that will clearly be harder (i.e., at least require
a slightly elaborate wrapper) after this change?
Sorting tuples, where the second item in the tuple should
have the
On Mar 13, 5:10 pm, Mark Dickinson [EMAIL PROTECTED] wrote:
(1, '14') represents 14
should be -14, of course.
--
http://mail.python.org/mailman/listinfo/python-list
Mark Dickinson wrote:
Sorting tuples, where the second item in the tuple should
have the opposite ordering to the first is going to be
a bit of a pain. Or even worse, where the ordering of the
second item depends on the value of the first item in the
tuple.
This is like some
On Mar 13, 7:38 pm, Alan Isaac [EMAIL PROTECTED] wrote:
Mark Dickinson wrote:
Sorting tuples, where the second item in the tuple should
have the opposite ordering to the first is going to be
a bit of a pain. Or even worse, where the ordering of the
second item depends on the value of the
On Mar 13, 8:38 pm, Alan Isaac [EMAIL PROTECTED] wrote:
Does this do it? ::
key= lambda x: (-x[1],int(x2))
Here I am depending on the lexicographic sorting of tuples.
Without that there would be real trouble.
Close. :-)
I think it needs to be something like:
key = lambda x: (-x[0],
Dan Bishop wrote:
Even assuming you meant (-x[0], int(x[1])), that sorts negative
numbers in the wrong order. You want
key = lambda x: (-1 if x[0] else 1) * int(x[1])
Sorry, was speed typing (very badly) and the question
actually had two different problem descriptions.
As you
I was surprised to see that
comparison is slated for death
in Python 3000.
For example:
http://www.python.org/dev/peps/pep-3100/
list.sort() and builtin.sorted() methods: eliminate cmp parameter [27]
[done]
But there is a rumor of a PEP to restore comparisons.
On Mar 12, 4:51 pm, Alan Isaac [EMAIL PROTECTED] wrote:
I was surprised to see that
comparison is slated for death
in Python 3000.
For example:http://www.python.org/dev/peps/pep-3100/
list.sort() and builtin.sorted() methods: eliminate cmp parameter
[27] [done]
Hmm, wasn't aware
Carl Banks [EMAIL PROTECTED] writes:
For example:http://www.python.org/dev/peps/pep-3100/
list.sort() and builtin.sorted() methods: eliminate cmp parameter
[27] [done]
Hmm, wasn't aware they were taking it that far. You should almost
always avoid using the cmp parameter because
Paul Rubin wrote:
The cmp option should not be removed. However, requiring
it to be specified as a keyword parameter instead of just
passed as an unlabelled arg is fine.
Sure; I would have no problem with that.
But that is not what is happening.
As for Carl's suggestion to use
| Hmm, wasn't aware they were taking it that far. You should almost
| always avoid using the cmp parameter because it's very inefficient;
|
| I don't see what's so inefficient about it necessarily.
The key function is called once per list item, for n calls total. The
comparision function is
On Mar 12, 6:52 pm, Alan Isaac [EMAIL PROTECTED] wrote:
Paul Rubin wrote:
The cmp option should not be removed. However, requiring
it to be specified as a keyword parameter instead of just
passed as an unlabelled arg is fine.
Sure; I would have no problem with that.
But that is not
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