🌐 Mailman 3 October 2013 - Python-list - python.org

Re: Thoughts on SQL vs ORM
by rusi June 11, 2014

June 11, 2014

On Feb 6, 5:58 pm, Andriy Kornatskyy <andriy.kornats...(a)live.com> wrote: > The question of persistence implementation arise often. I found repository pattern very valuable due to separation of concerns, mediate between domain model and data source (mock, file, database, web service, etc). > > The database data source is somewhat specific since you can proceed with SQL functions or ORM. Here are some thoughts why you might prefer SQL functions over ORM in your next project: > > http://mindref.blogspot.com/2013/02/sql-vs-orm.html > > Comments or suggestions are welcome. > > Thanks. > > Andriy Kornatskyy Interesting read. Your first 2 points: 1. It is not valid to think that relational model in database is domain model of application. They are different (except some trivial cases). 2. … Design your domain model with plain objects only And then later you go on to recommend SQL over ORM. So its not clear which side you are on! My own very preliminary thoughts on this: SQL is basically a functional language. OOP is just imperative programming with some syntactic sugar, name- spacing etc. IOW OOP is a lower level paradigm than FP because it deals with the 'how' more than the 'what.' Object-relational impedance mismatch happens because of the opposite reason to what people seem to believe: Because the higher-level SQL is pulled down into the lower-level OO mindset and not the other way around

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Re: Python GUI?
by eamonnrea＠gmail.com June 2, 2014

June 2, 2014

On Thursday, September 12, 2013 6:05:14 AM UTC+1, Michael Torrie wrote: > On 09/11/2013 02:55 PM, eamonnrea(a)gmail.com wrote: > > > PyQT -- You have a GUI designer, so I'm not going to count that > > > > What do you mean? Gtk has a GUI designer too. what of it? > > > > > I, personally, really like wxPython, but I also really like Tkinter. > > > I've messed with PyGTK, but I'd choose wxPython over it. > > > > Not me. wxWidgets' event model is way too MFC-esque for me. Does it > > still use event numbers that you define? Shudder. > > > > Gtk and Qt's method of signals and slots is by far the most powerful and > > flexible. > > > > > Have you got anything to say on what one I should be using(excluding > > > PyQT because it has a D&D designer >:( )? Is Tkinter really dead? > > > Should I stick with wxPython? > > > > I still don't understand why you are excluding Qt. All modern toolkits > > are heading towards imperative GUI design. With Gtk I use Glade and > > GtkBuilder. My GUI is in a nice XML file that gets loaded and > > manipulated by my python class. It's extremely clean. And in the case > > of compiled programming, you don't have to recompile just to tweak > > something like a layout. > > > > At the moment if someone were to come in from scratch and ask what GUI > > toolkit to use, I would answer Qt with PySide. It's the most > > cross-platform of all the toolkits, and it's one of the most mature. > > Gtk is also good, but Windows and Mac support is always lagging behind > > X11, and it's not as good at fitting into the native look and feel. > > > > > Also, with wxPython, it has kind of a "flow" layout like JFrame, > > > whereas it will adjust it's layout to look like a native Mac App, > > > Windows app or Linux App, correct? It'll look almost identical, > > > right? Not that it matters, I'm just curious! :D > > > > Possibly. I know Qt and Gtk both can flip the button orders, etc to > > look more native. And all good toolkits give you layout managers so you > > never have to resort to fixed layouts. Qt's layout system is very > > different than Gtk's, but once you get the feel of it (use the Qt > > Designer program!), it makes a lot of sense. I didn't realise GTK has a GUI designer too :( I don't like it when you can D&D to position things. I don't understand why someone wouldn't want to write the positioning code, and have fun with the debugging. That's the best part about writing a program, in my opinion. I'm against D&D with programming, and I'm not sure why.

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Standard Delay Format (SDF) Parsing
by moogyd May 26, 2014

May 26, 2014

Hi, A Standard Delay Format (SDF) file is a text file used to store delay information, and is used in ASIC design. I need to parse some of these files and before I re-invent the wheel, is anyone aware of a module to allow parsing of these files? Thanks, Steven

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daemon.DaemonContext and logging
by Sean DiZazzo May 22, 2014

May 22, 2014

I'm finally getting around to trying out the python-daemon module and have hit a wall. I'm trying to set up logging inside of the "with daemon.DaemonContext" block. But when I try to use a logger inside the block it throws an error: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ from __future__ import with_statement import logging import logging.handlers import daemon import daemon.pidlockfile import sys logger = logging.getLogger("DaemonLog") logger.setLevel(logging.INFO) formatter = logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s") handler = logging.FileHandler("log.file") logger.addHandler(handler) pid = daemon.pidlockfile.TimeoutPIDLockFile("/var/run/daemontest.pid", 10) with daemon.DaemonContext(pidfile=pid, gid=0, uid=0, stdout=sys.stdout, stderr=sys.stderr): logger.info("POO") ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I get the following traceback: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [seans_imac:~/Downloads] halfitalian% Traceback (most recent call last): File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/logging/__init__.py", line 753, in emit self.flush() File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/logging/__init__.py", line 731, in flush self.stream.flush() IOError: [Errno 9] Bad file descriptor Error in atexit._run_exitfuncs: Traceback (most recent call last): File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/atexit.py", line 24, in _run_exitfuncs func(*targs, **kargs) File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/logging/__init__.py", line 1355, in shutdown h.close() File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/logging/__init__.py", line 784, in close self.stream.close() IOError: [Errno 9] Bad file descriptor Error in sys.exitfunc: Traceback (most recent call last): File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/atexit.py", line 24, in _run_exitfuncs func(*targs, **kargs) File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/logging/__init__.py", line 1355, in shutdown h.close() File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/logging/__init__.py", line 784, in close self.stream.close() IOError: [Errno 9] Bad file descriptor ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Any advice? Also, I left in the call to TimeoutPIDLockfile() as well, because the library's documentation is pretty sparse, and I want to know if I'm using it properly. Thanks in advance. ~Sean

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daemon.DaemonContext
by Rebelo May 22, 2014

May 22, 2014

i get : IOError: [Errno 9] Bad file descriptor when i have logging and using daemon.DaemonContext() i tried passing : fh = logging.handlers.TimedRotatingFileHandler(LOG_FILENAME, 'midnight', encoding='utf-8') with : context = daemon.DaemonContext() context.files_preserve=[fh] but no good what am i doing wrong?

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Re: urllib with x509 certs
by Lacrima May 16, 2014

May 16, 2014

On Jul 4, 11:24 am, Chris Rebert <c...(a)rebertia.com> wrote: > On Sat, Jul 4, 2009 at 1:12 AM, Lacrima<Lacrima.Ma...(a)gmail.com> wrote: > > Hello! > > > I am trying to use urllib to fetch some internet resources, using my > > client x509 certificate. > > I have divided my .p12 file into mykey.key and mycert.cer files. > > Then I use following approach: > >>>> import urllib > >>>> url = 'https://example.com' > >>>> xml = '''<request> > > ... <somexml>somexml</somexml> > > </request>''' > >>>> opener = urllib.URLopener(key_file = 'mykey.key', cert_file = 'mycert.cer') > >>>> f = opener.open(url, xml) > > > This works Ok! But every time I am asked to enter PEM pass phrase, > > which I specified during dividing my .p12 file. > > So my question... What should I do to make my code fetch any url > > automatically (without asking me every time to enter pass phrase)? > > As I understand there is impossible to specify pass phrase while > > constructing URLopener. > > So what should I do? > > Subclass FancyURLopener > [http://docs.python.org/library/urllib.html#urllib.FancyURLopener], > overriding the prompt_user_passwd() method > [http://docs.python.org/library/urllib.html#urllib.FancyURLopener.prom...]. > Then use an instance of your subclass instead of URLopener. > > Cheers, > Chris > --http://blog.rebertia.com Hi Chris, Thanks for your quick reply. According to docs the return value of prompt_user_passwd() method should be a tuple (user, password), but there is no user when authenticating with certificate. So how should I use this method? This doesn't work: >>> import urllib >>> class MyOpener(urllib.FancyURLopener): ... def prompt_user_passwd(self, host, realm): ... return ('password') ... With regards, Max

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How to tell Script to use pythonw.exe ?
by goldtech May 7, 2014

May 7, 2014

Hi, Using Windows.... I want to run a .py file script using pythonw.exe so the DOS box will not open. Is there a way from inside the script to say "run me with pythonw.exe and not python.exe"? Thanks

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First attempt at a Python prog (Chess)
by Chris Hinsley April 30, 2014

April 30, 2014

New to Python, which I really like BTW. First serious prog. Hope you like it. I know it needs a 'can't move if your King would be put into check' test. But the weighted value of the King piece does a surprising emergent job. #!/usr/bin/python -tt # -*- coding: utf-8 -*- # Copyright (C) 2013 Chris Hinsley, GPL V3 License import sys import random import os PLY = 3 EMPTY = 0 BLACK = 1 WHITE = 2 NO_CAPTURE = 3 MAY_CAPTURE = 4 MUST_CAPTURE = 5 def piece_type(piece): return EMPTY if piece == 32 else BLACK if chr(piece) in 'KQRBNP' else WHITE def display_board(board): print ' a b c d e f g h' print '+---+---+---+---+---+---+---+---+' for row in range(8): for col in range(8): sys.stdout.write('| ') sys.stdout.write(chr(board[row * 8 + col])) sys.stdout.write(' ') sys.stdout.write('|') print 8 - row print '+---+---+---+---+---+---+---+---+' def piece_moves(board, index, dx, dy, capture_flag, distance): piece = board[index] type = piece_type(piece) cx = index % 8 cy = index / 8 for step in range(distance): nx = cx + (dx * (step + 1)) ny = cy + (dy * (step + 1)) if nx in range(8) and ny in range(8): newindex = ny * 8 + nx newpiece = board[newindex] newtype = piece_type(newpiece) if capture_flag == MUST_CAPTURE: if newtype != EMPTY and newtype != type: board[index] = ' ' if (ny == 0 or ny == 7) and chr(piece) in 'Pp': for promote in 'QRBN' if type == BLACK else 'qrbn': board[newindex] = promote yield board else: board[newindex] = piece yield board board[index], board[newindex] = piece, newpiece elif capture_flag == MAY_CAPTURE: if newtype == EMPTY or newtype != type: board[index], board[newindex] = ' ', piece yield board board[index], board[newindex] = piece, newpiece break elif newtype == EMPTY: board[index] = ' ' if (ny == 0 or ny == 7) and chr(piece) in 'Pp': for promote in 'QRBN' if type == BLACK else 'qrbn': board[newindex] = promote yield board else: board[newindex] = piece yield board board[index], board[newindex] = piece, newpiece else: break def pawn_moves(board, index, options): for x, y, flag, distance in options: for new_board in piece_moves(board, index, x, y, flag, distance): yield new_board def other_moves(board, index, options, distance): for x, y in options: for new_board in piece_moves(board, index, x, y, MAY_CAPTURE, distance): yield new_board def black_pawn_moves(board, index): distance = 2 if index in range(8, 16) else 1 for new_board in pawn_moves(board, index, [(0, 1, NO_CAPTURE, distance), (-1, 1, MUST_CAPTURE, 1), (1, 1, MUST_CAPTURE, 1)]): yield new_board def white_pawn_moves(board, index): distance = 2 if index in range(48, 56) else 1 for new_board in pawn_moves(board, index, [(0, -1, NO_CAPTURE, distance), (-1, -1, MUST_CAPTURE, 1), (1, -1, MUST_CAPTURE, 1)]): yield new_board def rook_moves(board, index): for new_board in other_moves(board, index, [(0, -1), (-1, 0), (0, 1), (1, 0)], 7): yield new_board def bishop_moves(board, index): for new_board in other_moves(board, index, [(-1, -1), (-1, 1), (1, 1), (1, -1)], 7): yield new_board def knight_moves(board, index): for new_board in other_moves(board, index, [(-2, 1), (2, -1), (2, 1), (-1, -2), (-1, 2), (1, -2), (1, 2)], 1): yield new_board def queen_moves(board, index): for new_board in bishop_moves(board, index): yield new_board for new_board in rook_moves(board, index): yield new_board def king_moves(board, index): for new_board in other_moves(board, index, [(0, -1), (-1, 0), (0, 1), (1, 0), (-1, -1), (-1, 1), (1, 1), (1, -1)], 1): yield new_board moves = {'P' : black_pawn_moves, 'p' : white_pawn_moves, \ 'R' : rook_moves, 'r' : rook_moves, \ 'B' : bishop_moves, 'b' : bishop_moves, \ 'N' : knight_moves, 'n' : knight_moves, \ 'Q' : queen_moves, 'q' : queen_moves, \ 'K' : king_moves, 'k' : king_moves} def all_moves(board, turn): for index, piece in enumerate(board): if piece_type(piece) == turn: for new_board in moves[chr(piece)](board, index): yield new_board piece_values = {'K' : (1000000, 0), 'k' : (0, 1000000), \ 'P' : (1, 0), 'p' : (0, 1), \ 'N' : (3, 0), 'n' : (0, 3), \ 'B' : (3, 0), 'b' : (0, 3), \ 'R' : (5, 0), 'r' : (0, 5), \ 'Q' : (9, 0), 'q' : (0, 9)} position_values = [0, 0, 0, 0, 0, 0, 0, 0, \ 0, 1, 1, 1, 1, 1, 1, 0, \ 0, 1, 2, 2, 2, 2, 1, 0, \ 0, 1, 2, 3, 3, 2, 1, 0, \ 0, 1, 2, 3, 3, 2, 1, 0, \ 0, 1, 2, 2, 2, 2, 1, 0, \ 0, 1, 1, 1, 1, 1, 1, 0, \ 0, 0, 0, 0, 0, 0, 0, 0] def score_board(board): black_score, white_score = 0, 0 for index, piece in enumerate(board): type = piece_type(piece) if type != EMPTY: position_value = position_values[index] if type == BLACK: black_score += position_value else: white_score += position_value black_value, white_value = piece_values[chr(piece)] black_score += black_value white_score += white_value return (black_score, white_score) def turn_score(board, turn): black_score, white_score = score_board(board) return (white_score - black_score) if turn == WHITE else (black_score - white_score) def best_move(board, turn, ply): best_score = -10000000 best_boards = [] for new_board in all_moves(board, turn): if ply: next_turn = BLACK if turn == WHITE else WHITE score = turn_score(best_move(new_board, next_turn, ply - 1), turn) else: score = turn_score(new_board, turn) if score > best_score or not best_boards: best_score = score best_boards = [new_board[:]] elif score == best_score: best_boards.append(new_board[:]) if best_boards: return random.choice(best_boards) return board[:] def main(): board = bytearray('RNBQKBNRPPPPPPPP pppppppprnbqkbnr') turn = WHITE while True: board = best_move(board, turn, PLY) turn = BLACK if turn == WHITE else WHITE os.system('clear') display_board(board) #raw_input() if __name__ == '__main__': main()

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How to get final URL after redirection
by nishant bhakta April 27, 2014

April 27, 2014

I have a link that will redirect to any-other link and i have to work with that final link. For example if i have a link "www.bit.ly/2V6CFi" that will redirect to "www.google.com". Here i want that i take "www.bit.ly/2V6CFi" and find the final redirect link and append "#q=python" to that link and produce an output that is "www.google.com/#q=python".

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Installing PyGame?
by Eam onn April 25, 2014

April 25, 2014

Perhaps this isn't the right place to post this, but it's the only place I could find. I asked yesterday or the day before about Python Game Development, and have found a few tutorials on PyGame. Now I have a bigger problem: HOW THE HECK DO I INSTALL PYGAME!?!?! System Details: • Mac OS X 10.8.4 Mountain Lion • 4GB DDR3 RAM I do have Window's installed, as well as Ubuntu 11.04 but I would like to use Mac OS X if possible. I've tried using MacPorts, Fink, the Mac DMG, source installing, installing NumPY, just about every way possible. I can't seem to get it working, I keep getting an error in all my versions of IDLE. I've tried: • IDLE 2.5 • IDLE 2.7.2 • IDLE 2.7.3 • IDLE 3.1 • IDLE 3.3.1 None of the versions work. I'm using PyGame 1.9.1. Thanks! Any help is appreciated!

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