multinomial combinations

I wrote a small generator function that produces multinomial combinations. (Python's itertools module does ordinary combinations, but not multinomial combinations). The code essentially works, except that the the last combination in each tuple is not enclosed in a nested tuple: In [2]: x= multi

strange behavior from recursive generator

A few weeks ago, I wrote a class that creates an iterator for solving the general unlabeled-balls-in-labeled boxes occupancy problem. Chris Rebert converted my code to a generator, which made the code cleaner, and I subsequently simplified it somewhat further. My problem is the following: All of

Re: recursive algorithm for balls in numbered boxes

Mark Dickinson-2 wrote: > > > This is a well-known trick: to divide 5 (unlabeled) balls amongst 3 > (labeled) boxes, you write down sequences of 5 o's and 2 x's, where > the o's represent the 5 balls and the 'x's represent dividers: > > ooxooxo -> [2, 2, 1] > xoooxoo -> [0, 3, 2] >

Re: recursive algorithm for balls in numbered boxes

Chris, Your code is much cleaner than mine. I will have to figure out exactly how it is working. Thanks! Phillip -- View this message in context: http://old.nabble.com/recursive-algorithm-for-balls-in-numbered-boxes-tp32440187p32443579.html Sent from the Python - python-list mailing list a

Re: recursive algorithm for balls in numbered boxes

Hello Peter, When I run my code, I get the same 14 configurations that your code produces; the only different that I can see in the output is that the configurations are produced in a different order. Note that your code is not creating an iterator, so thus doesn't do what I want. Also, generat

recursive algorithm for balls in numbered boxes

I've written a recursive class that creates an iterator to solve a general formulation of the combinatorics problem known as "balls in numbered boxes" (also known as "indistinguishable balls in distinguishable boxes"). The code has been extensively tested and appears to work, but isn't terribly e

Re: can't generate iterator from list

I just realized that there is a defect in my algorithm, so I will try to code this using a recursive algorithm instead. -- View this message in context: http://old.nabble.com/can%27t-generate-iterator-from-list-tp32435519p32439439.html Sent from the Python - python-list mailing list archive at

Re: can't generate iterator from list

Very nice explanation! I've circumvented the problem by returning a `deepcopy` of the list. I've also added an acknowledgment. The revised code is attached. I'd like to see both balls in numbered boxes (this code) and balls in unnumbered (indistinguishable) boxes in Python's `itertools` module

can't generate iterator from list

It is supposed to be possible to generate a list representation of any iterator that produces a sequence of finite length, but this doesn't always work. Here's a case where it does work: Input: from itertools import combinations list(combinations(range(4),2)) Output: [(0, 1), (0, 2), (0, 3), (

Re: can't generate list from iterator

The title should have been "can't generate list from iterator". -- View this message in context: http://old.nabble.com/can%27t-generate-iterator-from-list-tp32435519p32435569.html Sent from the Python - python-list mailing list archive at Nabble.com. -- http://mail.python.org/mailman/listinfo/

Re: Turtle graphics speed(). Seems broken

Stefan Behnel-3 wrote: > > alexander@gmail.com wrote: >> I think the speed function may be broken from the turtle graphics package >> >> >> "from turtle import * >> >> speed('fastest') >> >> forward(50)" >> >> >> I have tried all of the different speed settings, but I get no change >>

Re: how to convert string function to string method?

Bruno- You've made some excellent suggestions, and I'm always grateful for the opportunity to learn. My revised code appears below. Philllip def strip_pairs(s, open='([{\'"', close=')]}\'"'): """ OVERVIEW This function strips matching pairs of characters from the beginning and end

how to convert string function to string method?

I wrote a handy-dandy function (see below) called "strip_pairs" for stripping matching pairs of characters from the beginning and end of a string. This function works, but I would like to be able to invoke it as a string method rather than as a function. Is this possible? def strip_pairs(s=None

Re: How to create a docstring for a module?

OK. I was able to reproduce the problem. My difficulty was that the command that I issued initially was "from xyz import *" rather than just "import xyz". If I say "import xyz", then the docstring is defined; if I say "from xyz import *", it isn't. I'm not sure whether this is a bug or expecte

Re: How to create a docstring for a module?

Steven D'Aprano-7 wrote: > > On Sun, 06 Dec 2009 10:55:50 +0100, Andreas Waldenburger wrote: > >> On Sat, 5 Dec 2009 23:04:42 -0800 (PST) "Dr. Phillip M. Feldman" >> wrote: >> >> >>> If I create a module xyz.py with a docstring &quo

How to create a docstring for a module?

If I create a module xyz.py with a docstring """xyz does everything you could possibly want.""" at the top, the command ?xyz issued at the IPython prompt does not display this docstring. What am I doing wrong? -- View this message in context: http://old.nabble.com/How-to-create-a-docstring-for-

How to find number of line that is currently executing?

I would like to put a statement on line N of my program that prints the line number that is currently executing. This may sound fairly trivial, but I don't want to hard code the line number because N will change if lines are inserted or deleted above that point. Any advice will be appreciated. --

Re: Is there a better way to code variable number of return arguments?

I'm amazed that this works. I had not realized that x,y= [3,4] is equivalent to x= 3; y= 4 Python is rather clever. Thanks! To elaborate on Paul's answer, returning the list will also unpack it if you have it set up that way. E.g. def func(alist): return alist some_list = [1, 2] t

Is there a better way to code variable number of return arguments?

I currently have a function that uses a list internally but then returns the list items as separate return values as follows: if len(result)==1: return result[0] if len(result)==2: return result[0], result[1] (and so on). Is there a cleaner way to accomplish the same thing? -- View this messag

Re: comparison on list yields surprising result

It looks as though what I should have done is the following: In [23]: array(x) > 6 Out[23]: array([False, False, False, False], dtype=bool) -- View this message in context: http://www.nabble.com/comparison-on-list-yields-surprising-result-tp25195170p25195893.html Sent from the Python - python-l

comparison on list yields surprising result

In [21]: x Out[21]: [1, 2, 3, 5] In [22]: x>6 Out[22]: True Is this a bug? -- View this message in context: http://www.nabble.com/comparison-on-list-yields-surprising-result-tp25195170p25195170.html Sent from the Python - python-list mailing list archive at Nabble.com. -- http://mail.python.

Python 'for' loop is memory inefficient

I wrote the following correct but inefficient test of primality for purposes of demonstrating that the simplest algorithm is often not the most efficient. But, when I try to run the following code with a value of n that is large enough to produce a significant amount of running time, I get an out

Re: trouble with reload

> Could you please clarify how you're calling it? E.g. > reload('foo') > or > reload(foo) > > ? > > On Thu, 13 Aug 2009 12:05:26 -0700, Dr. Phillip M. Feldman > wrote: > >> According to the Python documentation, 'reload

trouble with reload

According to the Python documentation, 'reload' reloads a previously imported module (so that changes made via an external editor will be effective). But, when I try to use this command, I get the following error message: TypeError: reload() argument must be module Any suggestions will be appre

How to comment on a Python PEP?

Is there a mechanism for submitting comments on a Python PEP? -- View this message in context: http://www.nabble.com/How-to-comment-on-a-Python-PEP--tp24840417p24840417.html Sent from the Python - python-list mailing list archive at Nabble.com. -- http://mail.python.org/mailman/listinfo/python

Re: trouble with complex numbers

I am using Python 2.5, and most of the cmath functions are not yet available in this version. Thanks! Phillip P.S. In your code, that should be x+= 0J P.P.S. I wish that the documentation indicated anything that is new. Christian Heimes-2 wrote: > > > > phase() has been added to Python 2.

trouble with complex numbers

When I try to compute the phase of a complex number, I get an error message: In [3]: from cmath import * In [4]: x=1+1J In [5]: phase(x) NameError: name 'phase' is not defined AttributeError: 'complex' object has no attribute 'phase' Any advice will be appreciated. -- View this message in con

Re: possible to round number and convert to string?

This was very close to what I wanted. Thanks! My final code looks like this: def num2str(x,f=4): """Convert x (int or float) to a string with f digits to right of the decimal point. f may be zero or negative, in which case the decimal point is suppressed.""" s= str(round(x,f)) i

possible to round number and convert to string?

I'd like to be able to convert a float to a string representation in which the number is rounded to a specified number of digits. If num2str is a hypothetical function that does this, then num2str(pi,3) would be '3.142' (not '3.141'). I've been told that there is no such function in Python. I t

delayed sys.exit?

In the attached http://www.nabble.com/file/p24726902/test.py test.py code, it appears that additional statements execute after the call to sys.exit(0). I'll be grateful if anyone can shed light on why this is happening. Below is a copy of some sample I/O. Note that in the last case I get addit

Re: len() should always return something

in xs: print x Having to put such extra logic into practically every function is one of the annoying things about Python. Phillip Diez B. Roggisch-2 wrote: > > Dr. Phillip M. Feldman schrieb: >> Some aspects of the Python design are remarkably clever, while others >> leave >

Re: len() should always return something

"As far as I know, there is no programming language which treats scalars like ints as if they were vectors of length 1" Actually, Matlab does: >> length(5) ans = 1 >> -- View this message in context: http://www.nabble.com/len%28%29-should-always-return-something-tp24639361p24654358.html

Re: list vs. tuple [Re: len() should always return something]

isinstance(x, (int, float, complex)) is certainly very compact, and does what I want. Thanks! -- View this message in context: http://www.nabble.com/len%28%29-should-always-return-something-tp24639361p24654347.html Sent from the Python - python-list mailing list archive at Nabble.com. -- htt

len() should always return something

Some aspects of the Python design are remarkably clever, while others leave me perplexed. Here's an example of the latter: Why does len() give an error when applied to an int or float? len() should always return something; in particular, when applied to a scalar, it should return a value of 1. Of

PDF version of Python Tutorial?

Does anyone know if there is a PDF version of the Python Tutorial (URL= http://www.python.org/doc/current/tutorial/)? -- View this message in context: http://www.nabble.com/PDF-version-of-Python-Tutorial--tp24543817p24543817.html Sent from the Python - python-list mailing list archive at Nabble.

Re: missing 'xor' Boolean operator

Suppose that 'xor' returns the value that is true when only one value is true, and False otherwise. This definition of xor doesn't have the standard associative property, that is, (a xor b) xor c will not necessarily equal a xor (b xor c) To see that this is the case, let a= 1, b= 2, and c= 3

Re: missing 'xor' Boolean operator

I did initially ask for an infix xor operator, but eventually gave up on this. I like the first of your two one-line solutions below; this is clean and easy to understand. Thanks! I'd still like to be able to write an expression like '(a and b) xor (c and d) xor (e and f)', but it looks as thou

Re: missing 'xor' Boolean operator

arg in args: if bool(arg): result= not result return result MRAB-2 wrote: > > Ethan Furman wrote: >> Robert Kern wrote: >>> On 2009-07-14 14:56, Dr. Phillip M. Feldman wrote: >>> >>>> != does do what I want, except that it doesn't indicate

Re: missing 'xor' Boolean operator

to see an option for type checking on operands of logical operators, so that attempting to apply a logical operator to non-Boolean entities generates a warning message. With operand type checking, 'xor' and != would be different. Mark Dickinson wrote: > > On Jul 14, 7:25 pm, "D

missing 'xor' Boolean operator

Current Boolean operators are 'and', 'or', and 'not'. It would be nice to have an 'xor' operator as well. -- View this message in context: http://www.nabble.com/missing-%27xor%27-Boolean-operator-tp24485116p24485116.html Sent from the Python - python-list mailing list archive at Nabble.com. --