On Mon, Jan 19, 2015 at 11:52 PM, Devin Jeanpierre
wrote:
> On Mon, Jan 19, 2015 at 3:08 PM, Steven D'Aprano
> wrote:
>> Zachary Gilmartin wrote:
>>
>>> Why aren't there trees in the python standard library?
>>
>> Possibly because they aren't needed? Under what circumstances would you use
>> a tr
Terry Reedy :
> Others have answered as to why other special-purpose
> constrained-structure trees have not been added to the stdlib.
Ordered O(log n) mappings are not special-purpose data structures. I'd
say strings and floats are much more special-purpose than ordered
mappings, and yet Python h
On Tuesday, January 20, 2015 at 11:38:27 AM UTC+5:30, Terry Reedy wrote:
> On 1/19/2015 5:06 PM, Zachary Gilmartin wrote:
> > Why aren't there trees in the python standard library?
>
> Sequences nested withing sequences can be regarded as trees, and Python
> has these. I regard Lisp as a tree pr
On Tuesday, January 20, 2015 at 7:03:56 PM UTC+5:30, Rustom Mody wrote:
> On Tuesday, January 20, 2015 at 11:38:27 AM UTC+5:30, Terry Reedy wrote:
> > On 1/19/2015 5:06 PM, Zachary Gilmartin wrote:
> > > Why aren't there trees in the python standard library?
> >
> > Sequences nested withing sequen
On Mon, Jan 19, 2015 at 6:46 PM, Mark Lawrence
wrote:
> I don't know if you've seen this http://kmike.ru/python-data-structures/
> but maybe of interest.
>
I haven't read but also possibly of interest:
Data Structures and Algorithms in Python by Michael T. Goodrich, Roberto
Tamassia, Michael H.
Rustom Mody :
> Yeah python has trees alright.
Does Python balance them for you?
Marko
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On 20/01/2015 05:19, Marko Rauhamaa wrote:
Mark Lawrence :
On 19/01/2015 22:06, Zachary Gilmartin wrote:
Why aren't there trees in the python standard library?
Probably because you'd never get agreement as to which specific tree
and which specific implementation was the most suitable for inc
On Tuesday, January 20, 2015 at 7:46:02 PM UTC+5:30, Marko Rauhamaa wrote:
> Rustom Mody :
>
> > Yeah python has trees alright.
>
> Does Python balance them for you?
No
Does python support a menagerie of lists like C
- singly linked, doubly linked, with header, without header etc?
Or access to
Rick Johnson writes:
> No one here would justify a public business refusing to
> serve or employ a person based on race, religion, sex, or
> otherwise.
Depends on what you mean by "or otherwise".
> So why would you so easily discriminate against speech?
People discriminate amongst prospective
On Tue, Jan 20, 2015 at 6:33 AM, Rustom Mody wrote:
> from enum import Enum
> class TreeTag(Enum):
> I = 0 # An internal node
> L = 1 # A leaf node
> def __repr__(self): return self.name
>
> I = TreeTag.I
> L = TreeTag.L
Explicitly tagging nodes as internal or leaves is kind of ugl
Marko Rauhamaa writes:
> So in my Python software (both at work and at home) needs, I use a
> Python AVL tree implementation of my own. My use case is timers. (GvR
> uses heapq for the purpose.)
Have you benchmarked your version against heapq or even the builtin
sorting functions?
--
https://mai
Steven D'Aprano writes:
> Possibly because they aren't needed? Under what circumstances would
> you use a tree instead of a list or a dict or combination of both?
I've sometimes wanted a functional tree in the sense of functional
programming. That means the tree structure is immutable and you in
In a Masters for Data Science and need the help using Python/R mainly.
Please forward background(education, work) teaching experence in stats,
linear algebra, programming (Scikit, Panda, Numpy), timezone, and rates.
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>-Original Message-
>From: Python-list [mailto:python-list-
>bounces+crk=godblessthe...@python.org] On Behalf Of Rick Johnson
>Sent: Monday, January 19, 2015 8:06 PM
>To: python-list@python.org
>Subject: Re: Random ALL CAPS posts on this group
>
>On Monday, January 19, 2015 at 8:16:01 PM
Marko Rauhamaa writes:
> As I said, I use ordered mappings to implement timers... The downside
> of heapq is that canceled timers often flood the heapq structure...,
> GvR mentioned a periodic "garbage collection" as a potentially
> effective solution.
You could look up the "timer wheel" approac
On Tuesday, January 20, 2015 at 10:51:13 PM UTC+5:30, Ian wrote:
> On Tue, Jan 20, 2015 at 6:33 AM, Rustom Mody wrote:
> > from enum import Enum
> > class TreeTag(Enum):
> > I = 0 # An internal node
> > L = 1 # A leaf node
> > def __repr__(self): return self.name
> >
> > I = TreeTag
Say an object like this exists:
class test:
a = ""
b = ""
You pickle it.
You change the object definition to have a new field:
class test
a = ""
b = ""
c = ""
You read the pickled object.
Will it load but ignore the new field?
That is what I want.
--
https://mail.python.org/
On Tuesday, January 20, 2015 at 11:46:11 PM UTC+5:30, Rustom Mody wrote:
> On Tuesday, January 20, 2015 at 10:51:13 PM UTC+5:30, Ian wrote:
> > On Tue, Jan 20, 2015 at 6:33 AM, Rustom Mody wrote:
> > > # Converting to generators is trivial
> > > =
> >
> > :-)
>
> Less trivial
James Smith wrote:
> Say an object like this exists:
> class test:
> a = ""
> b = ""
>
> You pickle it.
>
> You change the object definition to have a new field:
> class test
> a = ""
> b = ""
> c = ""
>
> You read the pickled object.
> Will it load but ignore the new field?
Exactly. There are over 23,000 different kinds of trees. There's no way
you could get all of them to fit in a library, especially a standard
one. Instead, we prefer to provide people with the tools they need to
grow their own trees.
http://caseytrees.org/programs/planting/ctp/
http://www.ncsu.
There are similarly many kinds of hash tables.
For a given use case (e.g. a sorted dict, or a list with efficient
removal, etc.), there's a few data structures that make sense, and a
library (even the standard library) doesn't have to expose which one
was picked as long as the performance is good.
On Wed, Jan 21, 2015 at 7:15 AM, Ken Seehart wrote:
> Exactly. There are over 23,000 different kinds of trees. There's no way you
> could get all of them to fit in a library, especially a standard one.
> Instead, we prefer to provide people with the tools they need to grow their
> own trees.
I'm
Paul Rubin :
> Marko Rauhamaa writes:
>> So in my Python software (both at work and at home) needs, I use a
>> Python AVL tree implementation of my own. My use case is timers. (GvR
>> uses heapq for the purpose.)
>
> Have you benchmarked your version against heapq or even the builtin
> sorting fu
Paul Rubin :
> You could look up the "timer wheel" approach used by the Linux kernel
> and by Erlang. It's less general than an ordered map, but probably
> faster in practice.
>
> https://lkml.org/lkml/2005/10/19/46
>
> Has some info. I think the kernel uses a different method now though.
I
Hi
I have a file with a python scripts that has many functions in it. To run the
script I did the following:
1. $ python (to initiate python, using the python command)
2. >>> import file_name (without .py)
3. >>> file_name.function_name(argument) (to run the function_name with
argument (argument
On Tuesday, 20 January 2015 17:11:58 UTC-4, faiz@gmail.com wrote:
> Hi
>
> I have a file with a python scripts that has many functions in it. To run the
> script I did the following:
> 1. $ python (to initiate python, using the python command)
> 2. >>> import file_name (without .py)
> 3. >>>
In article ,
rustompm...@gmail.com says...
>
> Yeah python has trees alright.
>
> Heres' some simple tree-code
Didn't you just demonstrate that Python has no trees and instead you
have to implement them yourself (or use a third-party implementation)?
I don't know what's the point of all this
On Tuesday, January 20, 2015 at 3:22:55 PM UTC-6, André Roberge wrote:
> On Tuesday, 20 January 2015 17:11:58 UTC-4, faiz@gmail.com wrote:
> > Hi
> >
> > I have a file with a python scripts that has many functions in it. To run
> > the script I did the following:
> > 1. $ python (to initiate
On Mon, 19 Jan 2015 16:15:58 -0800, Luke Tomaneng wrote:
> Has anyone noticed these? There have been about three of them recently
> and they don't seem to have anything to do with Python at all. Does
> anyone know if there is a good reason they are here?
Abusive spam from idiots. I have a regex t
On 20/01/15 01:49, Dan Stromberg wrote:
I think probably the most common need for a tree is implementing a
cache,
That is probably true, at least if you're a squirrel.
--
https://mail.python.org/mailman/listinfo/python-list
On 20 January 2015 at 04:21, Dan Stromberg wrote:
> On Mon, Jan 19, 2015 at 6:46 PM, Mark Lawrence
> wrote:
>>
>> I don't know if you've seen this http://kmike.ru/python-data-structures/ but
>> maybe of interest.
>
> I've seen it. It's a nice page.
>
> I attempted to get my treap port in there s
On Wednesday, January 21, 2015 at 3:18:03 AM UTC+5:30, Mario wrote:
> rustompmody says...
> >
> > Yeah python has trees alright.
> >
> > Heres' some simple tree-code
>
> Didn't you just demonstrate that Python has no trees and instead you
> have to implement them yourself (or use a third-party
Rustom Mody writes:
> ## The depth first algorithm
> dfs (L x) = [x]
> dfs (B x lst rst) = [x] ++ dfs lst ++ dfs rst
Cute. I can't resist posting the similar breadth first algorithm:
bfs (L x) = [x]
bfs (B x lst rst) = bfs lst ++ [x] ++ bfs rst
> *Main> dfs t
> [6,2,1,4,3,5,8,7,9]
*
On Wednesday, January 21, 2015 at 7:19:39 AM UTC+5:30, Paul Rubin wrote:
> Rustom Mody writes:
> > ## The depth first algorithm
> > dfs (L x) = [x]
> > dfs (B x lst rst) = [x] ++ dfs lst ++ dfs rst
>
> Cute. I can't resist posting the similar breadth first algorithm:
>
> bfs (L x) = [x]
On 1/20/2015 4:47 PM, Mario wrote:
In article ,
rustompm...@gmail.com says...
Yeah python has trees alright.
Heres' some simple tree-code
Didn't you just demonstrate that Python has no trees and instead you
have to implement them yourself (or use a third-party implementation)?
I don't know
On 21/01/2015 01:22, Joshua Landau wrote:
On 20 January 2015 at 04:21, Dan Stromberg wrote:
On Mon, Jan 19, 2015 at 6:46 PM, Mark Lawrence wrote:
I don't know if you've seen this http://kmike.ru/python-data-structures/ but
maybe of interest.
I've seen it. It's a nice page.
I attempted to
in the program below i want it to make it work the same way as TRACERT
command . but i am not able to make it work the same way . for which i need
your help thank you
here is the program
#!/usr/bin/python
import socket
import struct
import sys
# We want unbuffered stdout so we can pr
On Tue, 20 Jan 2015 19:37:26 -0800, Chandrakant Tiwari wrote:
> in the program below i want it to make it work the same way as TRACERT
> command . but i am not able to make it work the same way . for which i
> need your help thank you
What is the difference between TRACERT and your Python s
On Tue, Jan 20, 2015 at 5:22 PM, Joshua Landau wrote:
> On 20 January 2015 at 04:21, Dan Stromberg wrote:
>> On Mon, Jan 19, 2015 at 6:46 PM, Mark Lawrence
>> wrote:
>>>
>>> I don't know if you've seen this http://kmike.ru/python-data-structures/ but
>>> maybe of interest.
>>
>> I've seen it. I
On Mon, 19 Jan 2015 16:12:57 -0800, Luke Tomaneng wrote:
> I have been having a bit of trouble with the things mentioned in the
> title.
I've uploaded a slightly different approach to your code at:
http://www.sined.co.uk/tmp/shop.py.txt
--
Denis McMahon, denismfmcma...@gmail.com
--
https://ma
On Tue, 20 Jan 2015 19:37:26 -0800, Chandrakant Tiwari wrote:
> in the program below i want it to make it work the same way as TRACERT
> command.
As an observation, you're re-inventing a wheel that already works
perfectly well, in that any failings of tracert tend to be more down to
the way r
On Tue, Jan 20, 2015 at 1:45 AM, Marko Rauhamaa wrote:
> Terry Reedy :
>
> > Others have answered as to why other special-purpose
> > constrained-structure trees have not been added to the stdlib.
>
> Ordered O(log n) mappings are not special-purpose data structures. I'd
> say strings and floats
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