🌐 Mailman 3 May 2006 - Python-list - python.org

Ricerca Programmatore Python
by Nic May 31, 2006

May 31, 2006

Please accept my apologies for the use of the Italian language. ************* Salve a tutti, Scrivo per informarvi di una proposta di collaborazione. Sto cercando un programmatore per la realizzazione di un mini-software utile per analizzare e rappresentare multigrafi. Si richiede una ottima competenza nell'utilizzo di Python con i relativi pacchetti di rappresentazione matematica (es. matplotlib). Per la nozione di grafo si rimanda alle seguenti pagine: http://it.wikipedia.org/wiki/Teoria_dei_grafi (italiano). http://en.wikipedia.org/wiki/Graph_theory (inglese). È preferibile la residenza in provincia di Milano, in vista di un possibile incontro. Si tratta di una collaborazione esterna retribuita. Gli interessati possono contattarmi direttamente ai recapiti presenti in coda all'e-mail, inviando il relativo curriculum vitae. Spero di avere fatto cosa gradita postando questo annuncio. In caso contrario, mi scuso per il disturbo. Saluti, Giandomenico Sica Polimetrica Onlus Corso Milano 26 20052 Monza Mi Italia Tel/Fax: 039.2301829 E-mail: g.sica chiocciola polimetrica.org

6 6

Re: An algorithm problem
by John Machin May 31, 2006

May 31, 2006

On 31/05/2006 4:58 PM, Bo Yang wrote: > Hi , > I have writen a python program to slove a problem described as below: > > (Forgive my poor English !) > > Put the 2^n 0 or 1 to form a ring , Sorry, I can't understand that. It would be very helpful if you wrote out (for example, when n == 3) what the "0-1 ring" looks like. Do you mean ring as in a circular buffer, or do you mean ring as in "groups, rings, and fields"? > and we can select any continuous n > ones from > the ring to constitute a binary number . And obviously we can get 2^n > selections , > so the question is : > Given a number n and you must > Povide an algorithm by which the 0-1 ring is produced , and the 2^n > number we get > are just from 0 to 2^n-1 uniquely and entirely . > > So I write the following program to slove the question , and it works > well for the n below 10 > > > flag = 0 > input = 10 Problem! See below. > number = 2**input > set = set() Problem!! > list = [] Problem!!! It is a very bad habit to re-use or "shadow" the names of built-in functions (input, set, list). Please stop now. Try to think of meaningful names for your input number, your set and your list. What do you think would happen if your code needed a second set and you wrote: set2 = set() ? > > def list2int(l , n ): Please don't use "l" (that's "L".lower()) as an identifier. It is far too easily confused with the digit "1" in many fonts. > ret = 0 > for x in l : > if( n == 0 ): Please lose the (); they are redundant. Please read http://www.python.org/dev/peps/pep-0008/ in particular the section on whitespace. (Please forgive my exceedingly poor putonghua!) Dui bu qi, women shi laowai -- we can't read our characters easily without the customary spacing. > break [snip] Your code appears without any indentation in the two newsreaders that I tried. As a result, I (and I presume others interested in helping you) can't read your code without a lot of guesswork, and certainly can't run it. Try changing leading tabs to spaces, and sending it again. Alternatively attach it as a file. Regards, John

1 0

Re: genexp performance problem?
by Giovanni Bajo May 31, 2006

May 31, 2006

Fredrik Lundh wrote: >> I found this strange: >> >> python -mtimeit "sum(int(L) for L in xrange(3000))" >> 100 loops, best of 3: 5.04 msec per loop >> >> python -mtimeit "import itertools; sum(itertools.imap(int, >> xrange(3000)))" 100 loops, best of 3: 3.6 msec per loop >> >> I thought the two constructs could achieve the same speed. > > hint: how many times to the interpreter have to look up the names > "int" > and "L" in the two examples ? Ah right, thanks! -- Giovanni Bajo

1 0

genexp performance problem?
by Giovanni Bajo May 31, 2006

May 31, 2006

Hello, I found this strange: python -mtimeit "sum(int(L) for L in xrange(3000))" 100 loops, best of 3: 5.04 msec per loop python -mtimeit "import itertools; sum(itertools.imap(int, xrange(3000)))" 100 loops, best of 3: 3.6 msec per loop I thought the two constructs could achieve the same speed. -- Giovanni Bajo

3 3

Watching serial port activity.
by xkenneth May 31, 2006

May 31, 2006

Hi, I'm writing a couple python applications that use the serial port (RS-232) quite extensively. Is there any way I can monitor all activity on the serial port and have it printed as the transactions occur? I'm trying to reverse engineer a microcontroller serial routine and I'd like to see any response the chip sends back. Regards, Ken

7 13

ideas for programs?
by Brandon McGinty May 31, 2006

May 31, 2006

Hi, I've been learning python for the past couple of months and writing misc scripts here and there, along with some web apps. I'm wondering if anyone has ideas of programs I might try my hand at making? I'd appreciate it if they don't use images, because I'm blind. Also, I'm thinking of hiring myself out as a free-lance programmer. Are there many individuals/companies which would aprove programs written in python? Most adds I've seen require the programmer have a strong grasp of c++ or java. Thanks much for all of your help. THX, Brandon McGinty

1 0

Re: shuffling elements of a list
by greenflame May 31, 2006

May 31, 2006

Zhang Fan wrote: > On 30 May 2006 20:18:19 -0700, greenflame <alikakakhel(a)yahoo.com> wrote: > > Second of all, I would like to have > > other methods of shuffling, prefererably riffle shuffling and just > > plain randomly arranging the elements of the list. > > The random module has a `shuffle' method. It "Shuffle the sequence x > in place". > It may be help for you I am sorry but this does not help much. In my version of python (2.3) this method does not seem to exist. Also from the documentation, it seems that this method would give a random number.

3 2

shuffling elements of a list
by greenflame May 31, 2006

May 31, 2006

I would like to make a function that takes a list, more specificaly a list of strings, and shuffles its elements, like a pile of cards. The following is a script I tryed to make that implements pile shuffling. ---------- testdeck = list('qwertyuiop') def pileshuffle(DECK, NUMPILES): """Split the deck given into NUMPILES piles. Then also put the piles""" \ """ together to make the deck again.""" # Define a list of lists which is the piles PILES = [[]] * NUMPILES card = 0 pilenum = 0 while card < len(DECK): PILES[pilenum].append(DECK[card]) card += 1 if pilenum < NUMPILES: pilenum += 1 else: pilenum = 0 print PILES ---------- First of all, this script tells me that an index is out of range. I cannot see why this would be so. Second of all, I would like to have other methods of shuffling, prefererably riffle shuffling and just plain randomly arranging the elements of the list. I very much appreciate any help. Thank you.

4 3

RE: genexp performance problem?
by Delaney, Timothy (Tim) May 31, 2006

May 31, 2006

Kent Johnson wrote: > Reusing the generator doesn't give a correct answer; after the first > sum() the generator is exhausted: Duh - good point. I forgot it was returning a generator object, not generator function. Tim Delaney

1 0

Re: genexp performance problem?
by Kent Johnson May 31, 2006

May 31, 2006

Delaney, Timothy (Tim) wrote: > python -mtimeit "sum(int(L) for L in xrange(3000))" > 100 loops, best of 3: 6.76 msec per loop > > python -mtimeit -s "g = (int(L) for L in xrange(3000))" "sum(g)" > 1000000 loops, best of 3: 1.09 usec per loop > > The generator comprehension needs to create a new generator each time > around. Reusing the generator doesn't give a correct answer; after the first sum() the generator is exhausted: In [1]: g=(int(L) for L in xrange(10)) In [2]: sum(g) Out[2]: 45 In [3]: sum(g) Out[3]: 0 Kent

1 0