Steven D'Aprano wrote:
You are confusing mathematical ordering with sorting a list. Here, I will
sort some mixed complex and real numbers for you. If you look at them
closely, you will even be able to work out the algorithm I used to sort
them.
1
1+0j
1+7j
2
2+3j
3+3j
3-3j
3+4j
4
Adriano Varoli Piazza wrote:
As far as I recall from Math Analysis, which I studied two months ago,
you can't sort complex numbers. It makes no sense. The reason being
(reading from my book), it's not possible to define an order that
preserves the properties of arithmetical operations on
Steven D'Aprano wrote:
On Sat, 30 Jul 2005 16:43:00 +, Adriano Varoli Piazza wrote:
If you want to treat numbers as strings, why not convert them before
sorting them?
Because that changes the object and throws away information.
I think he meant doing something like
- lst = ['2+2j',
Playing around with comparisons of functions (don't ask), I discovered an
interesting bit of unintuitive behaviour:
(lambda y: y) (lambda y: y)
False
Do the comparison again and things become even more bizarre:
(lambda y: y) (lambda y: y)
True
(lambda y: y) (lambda y: y)
False
This
Steven D'Aprano wrote:
Playing around with comparisons of functions (don't ask), I discovered an
interesting bit of unintuitive behaviour:
(lambda y: y) (lambda y: y)
False
Do the comparison again and things become even more bizarre:
(lambda y: y) (lambda y: y)
True
(lambda y: y)
Steven D'Aprano wrote:
Playing around with comparisons of functions (don't ask), I discovered an
interesting bit of unintuitive behaviour:
a = lambda y: y
b = lambda y: y
a
function lambda at 0xf70598ec
b
function lambda at 0xf7059844
a b
False
So I'm puzzled about how Python compares
On Sat, 30 Jul 2005 08:13:26 -0400, Peter Hansen wrote:
Beginners should not be comparing lambdas.
Neither should you. ;-)
Actually, yes I should, because I'm trying to make sense of the mess that
is Python's handling of comparisons. At least two difference senses of
comparisons is jammed
On Sat, 30 Jul 2005 14:20:50 +0200, tiissa wrote:
Steven D'Aprano wrote:
Playing around with comparisons of functions (don't ask), I discovered an
interesting bit of unintuitive behaviour:
a = lambda y: y
b = lambda y: y
a
function lambda at 0xf70598ec
b
function lambda at 0xf7059844
a b
Steven D'Aprano ha scritto:
On Sat, 30 Jul 2005 08:13:26 -0400, Peter Hansen wrote:
Beginners should not be comparing lambdas.
Neither should you. ;-)
Actually, yes I should, because I'm trying to make sense of the mess that
is Python's handling of comparisons. At least two difference
Adriano Varoli Piazza ha scritto:
As far as I recall from Math Analysis, which I studied two months ago,
you can't sort complex numbers. It makes no sense. The reason being
(reading from my book), it's not possible to define an order that
preserves the properties of arithmetical operations
Steven D'Aprano wrote:
On Sat, 30 Jul 2005 08:13:26 -0400, Peter Hansen wrote:
Beginners should not be comparing lambdas.
Neither should you. ;-)
Actually, yes I should, because I'm trying to make sense of the mess that
is Python's handling of comparisons. At least two difference senses
* Reinhold Birkenfeld [EMAIL PROTECTED] wrote:
Steven D'Aprano wrote:
1+0j == 1 0
True
(1+0j == 1) yields True, which is comparable to 0.
a == b c is equivalent to a == b and b c:
1 == 1+0j 0
Traceback (most recent call last):
File stdin, line 1, in ?
TypeError: cannot compare
On Sat, 30 Jul 2005 13:22:47 +, Adriano Varoli Piazza wrote:
As far as I recall from Math Analysis, which I studied two months ago,
you can't sort complex numbers. It makes no sense. The reason being
(reading from my book), it's not possible to define an order that
preserves the
On Sat, 30 Jul 2005 13:30:20 +, Adriano Varoli Piazza wrote:
But tell me, how do you think sort works if not with , , ==, = and =
? I'm really interested.
How do you sort words in a dictionary? Why does five come before four
when the number five is larger than the number four? Why does
Steven D'Aprano ha scritto:
It was easy. I never once asked myself whether some complex number was
greater or less than another, I just asked which one comes first in a
lexicographic sort?
The two questions are NOT the same, and it is an ugliness in an otherwise
beautiful language that
Steven D'Aprano ha scritto:
On Sat, 30 Jul 2005 13:30:20 +, Adriano Varoli Piazza wrote:
But tell me, how do you think sort works if not with , , ==, = and =
? I'm really interested.
How do you sort words in a dictionary? Why does five come before four
when the number five is
On Sat, 30 Jul 2005 15:32:45 +0200, Reinhold Birkenfeld wrote:
Um, I didn't ask to compare complex numbers using comparison operators. I
asked to sort a list. And please don't tell me that that sorting is
implemented with comparison operators. That just means that the
implementation is
Steven D'Aprano ha scritto:
On Sat, 30 Jul 2005 13:22:47 +, Adriano Varoli Piazza wrote:
As far as I recall from Math Analysis, which I studied two months ago,
you can't sort complex numbers. It makes no sense. The reason being
(reading from my book), it's not possible to define an order
Some indications:
for i in range(5):
... x = lambda x:x
... y = lambda y:y
... print x,y,xy,id(x)id(y)
...
function lambda at 0x00EE83F0 function lambda at 0x00EE8FB0
True True
function lambda at 0x00EE8AB0 function lambda at 0x00EE83F0
False False
function lambda at 0x00EE8FB0
Steven D'Aprano wrote:
It was easy. I never once asked myself whether some complex number was
greater or less than another, I just asked which one comes first in a
lexicographic sort?
The two questions are NOT the same, and it is an ugliness in an otherwise
beautiful language that Python
Georg Neis wrote:
* Reinhold Birkenfeld [EMAIL PROTECTED] wrote:
Steven D'Aprano wrote:
1+0j == 1 0
True
(1+0j == 1) yields True, which is comparable to 0.
a == b c is equivalent to a == b and b c:
Right. Stupid me :) Doesn't do much to the point, though.
1 == 1+0j 0
Traceback
they are similar enough in some contexts
as to cause confusion.
Well, you can order everything according to some specs, but you can't find a
default
sort order for everything. That's where custom comparison functions can help.
Correct me if I'm wrong, but is there a default order for complex number
On Sat, 30 Jul 2005 16:13:22 +, Adriano Varoli Piazza wrote:
Steven D'Aprano ha scritto:
It was easy. I never once asked myself whether some complex number was
greater or less than another, I just asked which one comes first in a
lexicographic sort?
The two questions are NOT the
Steven D'Aprano ha scritto:
Do you understand the difference between partial and total ordering, or
weakly and strongly ordered? When you do understand them, come back and
tell me again whether you still think lexicographic sorting has no meaning
whatsoever.
I think I answered this in
On Sat, 30 Jul 2005 16:43:00 +, Adriano Varoli Piazza wrote:
If you want to treat numbers as strings, why not convert them before
sorting them?
Because that changes the object and throws away information.
Here is a list, containing one complex number converted to a string, and
one
On Sat, 30 Jul 2005 17:57:20 +, Adriano Varoli Piazza wrote:
Steven D'Aprano ha scritto:
Do you understand the difference between partial and total ordering, or
weakly and strongly ordered? When you do understand them, come back and
tell me again whether you still think lexicographic
Steven D'Aprano wrote:
Um, I didn't ask to compare complex numbers using comparison operators. I
asked to sort a list. And please don't tell me that that sorting is
implemented with comparison operators. That just means that the
implementation is confusing numeric ordering with sort order.
Steven D'Aprano wrote:
Python already allows you to compare this is not a number with the float
5.0. Mathematically, that is meaningless, but I would bet money that
99.9% of programmers would demand that they should be able to sort the
list [this is not a number, 5.0]. Do you think that it is
On Sat, 30 Jul 2005 23:37:04 +1000, Steven D'Aprano [EMAIL PROTECTED] wrote:
On Sat, 30 Jul 2005 14:20:50 +0200, tiissa wrote:
Steven D'Aprano wrote:
Playing around with comparisons of functions (don't ask), I discovered an
interesting bit of unintuitive behaviour:
a = lambda y: y
b =
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