On Fri, 7 Jul 2017 03:38 am, Marko Rauhamaa wrote:
> Notice that Scheme refers directory to conventional RAM:
>
> Variables and objects such as pairs, vectors, and strings implicitly
> denote locations
That implies that it is impossible to implement Scheme:
- using a programming language where
On Fri, 7 Jul 2017 03:05 am, Marko Rauhamaa wrote:
> I believe the concept of an object is among the more difficult things
> for novice programmers to get.
True, but that has nothing to do with object identity. Inheritance, "is-a"
versus "has-a" relationships, when to write len(x) versus x.len()
On Fri, 7 Jul 2017 01:41 am, Marko Rauhamaa wrote:
> Here's how identity is dealt with in First-Order Logic:
>
>https://en.wikipedia.org/wiki/First-order_logic#Semantics>
>
> In other words, identity is mapped to the "sameness" in a domain of
> discourse.
Define "sameness".
> In Second-
Steve D'Aprano :
> On Fri, 7 Jul 2017 08:56 am, Marko Rauhamaa wrote:
>
>> Google finds a Dutch master's thesis from 2009 that gives formal
>> semantics to a subset of Python. I was interested in seeing how it
>> treated identity. Lo and behold:
>>
>>The is operator determines whether its ope
Can I somehow check from inside a Python script if the executing Python engine
is major version v2 or v3?
I am thinking about a code similar to
if (os.python-majorversion<3)
print hello
else
print (hello)
Additional question:
Is there a way to execute a python script with v3 python engine
On Wednesday, September 22, 2010 at 4:01:04 AM UTC+5:30, Hellmut Weber wrote:
> Hi list,
> I'm looking for a possibility to access the partiton inforamtion of a
> hard disk of my computer from within a python program.
>
> Googling I found the module 'parted' but didn't see any possibility to
> get
On Fri, 7 Jul 2017 10:34 am, Gregory Ewing wrote:
> Steve D'Aprano wrote:
>> Address refers to a position in space.
>
> Not always. A PO Box number can remain the same when its owner's
> location in space changes.
But the PO box itself does not change.
Pedantically, I guess it could: the post o
On Fri, 7 Jul 2017 08:56 am, Marko Rauhamaa wrote:
> Google finds a Dutch master's thesis from 2009 that gives formal
> semantics to a subset of Python. I was interested in seeing how it
> treated identity. Lo and behold:
>
>The is operator determines whether its operands are the same object.
On Fri, 7 Jul 2017 07:46 am, Chris Angelico wrote:
> A simple name lookup cannot, I believe, be messed with. Nor can a literal.
In principle, you could replace builtins or globals with a custom namespace that
performed some computation on name lookup. You might even be able to insert
some additio
On Thursday, July 6, 2017 at 9:57:43 PM UTC-5, Skip Montanaro wrote:
> I was trying to solve a problem and cannot determine how to filter 0's but
> not false.
>
>
> I'm typing on my phone so can't paste a session [...]
I have not tried any for myself, but there are a few Python
installations avail
On Thursday, July 6, 2017 at 10:00:36 PM UTC-5, Sayth Renshaw wrote:
> Is there an "is not" method that's not != so I can check is not false.
Maybe. Or maybe /not/. :-P"
One way to find out would be to fire up your python
interpretor, and do some interactive testing. Here, allow me
to cinge my ey
On Friday, 7 July 2017 12:46:51 UTC+10, Rick Johnson wrote:
> On Thursday, July 6, 2017 at 9:29:29 PM UTC-5, Sayth Renshaw wrote:
> > I was trying to solve a problem and cannot determine how to filter 0's but
> > not false.
> >
> > Given a list like this
> > ["a",0,0,"b",None,"c","d",0,1,False,0
On Fri, 07 Jul 2017 02:48:45 +, Stefan Ram wrote:
def isfalse( x ):
> ... return x == 0 and str( type( x )) == ""
> ...
>
Don't depend on string representations of objects, unless you know what
you're doing. Do this instead:
def isfalse(x):
return x == 0 and type(x) is b
I was trying to solve a problem and cannot determine how to filter 0's but
not false.
I'm typing on my phone so can't paste a session, so I will attempt to apply
the Socratic method, and ask: Do you understand why your attempts have
failed so far? In what way are False and 0 the same? In what res
On Thu, 06 Jul 2017 19:29:00 -0700, Sayth Renshaw wrote:
> I have tried or conditions of v == False etc but then the 0's being
> false also aren't moved. How can you check this at once?
Maybe this will help:
Python 3.5.3+ (default, Jun 7 2017, 23:23:48)
[GCC 6.3.0 20170516] on linux
On Thursday, July 6, 2017 at 9:29:29 PM UTC-5, Sayth Renshaw wrote:
> I was trying to solve a problem and cannot determine how to filter 0's but
> not false.
>
> Given a list like this
> ["a",0,0,"b",None,"c","d",0,1,False,0,1,0,3,[],0,1,9,0,0,{},0,0,9]
>
> I want to be able to return this list
On Wednesday, July 5, 2017 at 4:15:34 PM UTC-5, Terry Reedy wrote:
> On 7/5/2017 12:34 PM, jorge.conr...@cptec.inpe.br wrote:
>
> > I would like know dow can I select and get the value from
> > a list of values uisng widgets.
>
> One way is to learn tkinter and then learn to use the
> Listbox wid
I was trying to solve a problem and cannot determine how to filter 0's but not
false.
Given a list like this
["a",0,0,"b",None,"c","d",0,1,False,0,1,0,3,[],0,1,9,0,0,{},0,0,9]
I want to be able to return this list
["a","b",None,"c","d",1,False,1,3,[],1,9,{},9,0,0,0,0,0,0,0,0,0,0]
However if I f
On Fri, Jul 7, 2017 at 10:34 AM, Gregory Ewing
wrote:
> Steve D'Aprano wrote:
>>
>> Address refers to a position in space.
>
>
> Not always. A PO Box number can remain the same when its owner's
> location in space changes. And IP addresses notoriously fail to
> identify physical locations.
A posi
Steve D'Aprano wrote:
Address refers to a position in space.
Not always. A PO Box number can remain the same when its owner's
location in space changes. And IP addresses notoriously fail to
identify physical locations.
--
Greg
--
https://mail.python.org/mailman/listinfo/python-list
Chris Angelico :
> On Fri, Jul 7, 2017 at 7:10 AM, Marko Rauhamaa wrote:
>> Whether id() returns one such thing or not can't be discerned by a
>> Python program. What's more, for any compliant implementation of id(),
>> you can interpret the returned number as an address in some address
>> space
On Fri, Jul 7, 2017 at 7:10 AM, Marko Rauhamaa wrote:
> Steve D'Aprano :
>
>> An address is a concrete location or place, in other words a physical
>> position in some space, while identity is the abstract state or
>> quality of being identical (sameness), in other words a state of
>> being.
>
> W
Steve D'Aprano :
> An address is a concrete location or place, in other words a physical
> position in some space, while identity is the abstract state or
> quality of being identical (sameness), in other words a state of
> being.
Whether id() returns one such thing or not can't be discerned by a
In Python, "==" is not a reference equality operator (and I hate Java for
their misuse of the operator), so I absolutely disagree with using the Java
description to describe Python's "==" operator, primarily because, well,
it's wrong. Simple example:
With Python 3.5.2 (should hold for any version
Sorry, finger twitch. Wish there were a minute grace period to recall
such mistakes.
On 7/6/2017 2:16 PM, Terry Reedy wrote:
--
Terry Jan Reedy
--
https://mail.python.org/mailman/listinfo/python-list
On 7/6/2017 11:41 AM, Marko Rauhamaa wrote:
Chris Angelico :
The formal definition is that objects have identities, and that
assignment (including function parameters and return values) gives you
a reference to the same object.
My example didn't contain a single assignment, but a variation of
On Fri, 7 Jul 2017 01:21 am, Marko Rauhamaa wrote:
> Steve D'Aprano :
>
>> On Thu, 6 Jul 2017 07:24 pm, Marko Rauhamaa wrote:
>>
>>> While talking about addresses might or might not be constructive, let
>>> me just point out that there is no outwardly visible distinction
>>> between "address" or
Marko Rauhamaa :
> Notice that Scheme refers directory to conventional RAM:
s/directory/directly/
--
https://mail.python.org/mailman/listinfo/python-list
Ian Kelly :
> On Thu, Jul 6, 2017 at 9:41 AM, Marko Rauhamaa wrote:
>> As a good example of the style I'm looking for, take a look at:
>>
>>https://docs.oracle.com/javase/specs/jls/se7/html/jls-17.html>
>
> Java reference types have basically the same concept of identity as
> Python objects,
On 06/07/17 17:53, ofekmeis...@gmail.com wrote:
Do you better understand what Privy is for now? If so, is there anything in
particular you think could be made more clear in the docs?
I think the point is that you failed to include any context in your
advert. An unadorned link in a post will
On Fri, Jul 7, 2017 at 3:05 AM, Marko Rauhamaa wrote:
> Chris Angelico :
>
>> On Fri, Jul 7, 2017 at 1:21 AM, Marko Rauhamaa wrote:
>>> What I'm looking for is snippets of Python code that illustrate the
>>> difference.
>>>
>>> That's how you can illustrate the difference between the "==" and "is
Chris Angelico :
> On Fri, Jul 7, 2017 at 1:21 AM, Marko Rauhamaa wrote:
>> What I'm looking for is snippets of Python code that illustrate the
>> difference.
>>
>> That's how you can illustrate the difference between the "==" and "is"
>> operators:
>>
>> >>> ["a"] is ["a"]
>> False
>>
Do you better understand what Privy is for now? If so, is there anything in
particular you think could be made more clear in the docs?
--
https://mail.python.org/mailman/listinfo/python-list
On Thu, Jul 6, 2017 at 9:41 AM, Marko Rauhamaa wrote:
> As a good example of the style I'm looking for, take a look at:
>
>https://docs.oracle.com/javase/specs/jls/se7/html/jls-17.html>
Java reference types have basically the same concept of identity as
Python objects, so I dug around to find
On Fri, Jul 7, 2017 at 1:21 AM, Marko Rauhamaa wrote:
> Steve D'Aprano :
>
>> On Thu, 6 Jul 2017 07:24 pm, Marko Rauhamaa wrote:
>>
>>> While talking about addresses might or might not be constructive, let
>>> me just point out that there is no outwardly visible distinction
>>> between "address" o
On Fri, Jul 7, 2017 at 12:59 AM, Marko Rauhamaa wrote:
>> Or you are using "address" in some abstract sense so that the "address"
>> does not change when the internal representation of the object is moved
>> to another location.
>
> "Address" is just a word. In fact, I don't think there is any def
Marko Rauhamaa writes:
> Jussi Piitulainen:
>
>> For me it's enough to know that it's the object itself that is passed
>> around as an argument, as a returned value, as a stored value, as a
>> value of a variable. This is the basic fact that lets me understand
>> the behaviour and performance of p
On Fri, Jul 7, 2017 at 12:56 AM, MRAB wrote:
> Perhaps you should be thinking of it as passing around the end of a piece of
> string, the other end being tied to the object itself. :-)
You mean like Elbonian currency?
http://dilbert.com/strip/2008-09-15
ChrisA
--
https://mail.python.org/mailma
Chris Angelico :
> The formal definition is that objects have identities, and that
> assignment (including function parameters and return values) gives you
> a reference to the same object.
My example didn't contain a single assignment, but a variation of your
statement would make a good part in
MRAB writes:
> On 2017-07-06 15:29, Jussi Piitulainen wrote:
>> Marko Rauhamaa writes:
>>
>>> While talking about addresses might or might not be constructive,
>>> let me just point out that there is no outwardly visible distinction
>>> between "address" or "identity".
>>
>> With a generational o
Steve D'Aprano :
> On Thu, 6 Jul 2017 07:24 pm, Marko Rauhamaa wrote:
>
>> While talking about addresses might or might not be constructive, let
>> me just point out that there is no outwardly visible distinction
>> between "address" or "identity".
>
> Er, yes there is. Address refers to a positio
Jussi Piitulainen :
> Marko Rauhamaa writes:
>
>> While talking about addresses might or might not be constructive, let
>> me just point out that there is no outwardly visible distinction
>> between "address" or "identity".
>
> With a generational or otherwise compacting garbage collector there
>
On 2017-07-06 15:29, Jussi Piitulainen wrote:
Marko Rauhamaa writes:
While talking about addresses might or might not be constructive, let
me just point out that there is no outwardly visible distinction
between "address" or "identity".
With a generational or otherwise compacting garbage coll
On Thu, Jul 6, 2017 at 7:24 PM, Marko Rauhamaa wrote:
> While talking about addresses might or might not be constructive, let me
> just point out that there is no outwardly visible distinction between
> "address" or "identity".
>
> Equally well, we could replace those words with:
>
>serial num
Marko Rauhamaa writes:
> While talking about addresses might or might not be constructive, let
> me just point out that there is no outwardly visible distinction
> between "address" or "identity".
With a generational or otherwise compacting garbage collector there
would be. I believe that to be a
On Thu, 6 Jul 2017 07:24 pm, Marko Rauhamaa wrote:
> While talking about addresses might or might not be constructive, let me
> just point out that there is no outwardly visible distinction between
> "address" or "identity".
Er, yes there is. Address refers to a position in space. Identity refer
On Thu, 6 Jul 2017 06:51 pm, Dan Wissme wrote:
> So what 'del L[i]' do exactly in memory ? Same as L.pop(i) ? with
> complexity O(n-i) ?
It depends on what L is and what the value of i is. If L is a list, and i is the
last index of the list, then deleting it is quick. If i is 0, then Python has
t
Chris Angelico :
> On Thu, Jul 6, 2017 at 5:35 PM, Jussi Piitulainen
> wrote:
>> Incidentally, let no one point out that ids are not memory addresses.
>> It says in the interactive help that they are (Python 3.4.0):
>> [...]
>
> Sorry, not the case.
> [...]
>
> id(...)
> Return the identity o
Le 06/07/2017 à 09:29, Terry Reedy a écrit :
On 7/6/2017 3:08 AM, Dan Wissme wrote:
I thought that del L[i] would slide L[i+1:] one place to the left,
filling the hole, but :
>>> L
[0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
>>> id(L)
4321967496
>>> id(L[5])# address of 50 ?
4297625504
Chris Angelico writes:
> On Thu, Jul 6, 2017 at 5:35 PM, Jussi Piitulainen
> wrote:
>> Incidentally, let no one point out that ids are not memory addresses.
>> It says in the interactive help that they are (Python 3.4.0):
>>
>> Help on built-in function id in module builtins:
>>
>> id(...)
>>
Le 06/07/2017 à 09:29, Terry Reedy a écrit :
On 7/6/2017 3:08 AM, Dan Wissme wrote:
I thought that del L[i] would slide L[i+1:] one place to the left,
filling the hole, but :
>>> L
[0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
>>> id(L)
4321967496
>>> id(L[5])# address of 50 ?
4297625504
On Thu, Jul 6, 2017 at 5:35 PM, Jussi Piitulainen
wrote:
> Incidentally, let no one point out that ids are not memory addresses.
> It says in the interactive help that they are (Python 3.4.0):
>
> Help on built-in function id in module builtins:
>
> id(...)
> id(object) -> integer
>
> Retu
Dan Wissme writes:
> I thought that del L[i] would slide L[i+1:] one place to the left,
> filling the hole, but :
>
L
> [0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
id(L)
> 4321967496
id(L[5])# address of 50 ?
> 4297625504
del L[2]
id(L[4]) # new address of 50 ?
>
On 7/6/2017 3:08 AM, Dan Wissme wrote:
I thought that del L[i] would slide L[i+1:] one place to the left,
filling the hole, but :
>>> L
[0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
>>> id(L)
4321967496
>>> id(L[5])# address of 50 ?
4297625504
>>> del L[2]
>>> id(L[4]) # new address
I thought that del L[i] would slide L[i+1:] one place to the left,
filling the hole, but :
>>> L
[0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
>>> id(L)
4321967496
>>> id(L[5])# address of 50 ?
4297625504
>>> del L[2]
>>> id(L[4]) # new address of 50 ?
4297625504
>>> id(L)
4321967496
So
55 matches
Mail list logo
