🌐 Mailman 3 June 2005 - Tutor - python.org

Postgresql+Python -tutorial?
by Olli Rajala Feb. 11, 2006

Feb. 11, 2006

Hi! I've been using MySQL up this day, but would like to convert my program to use Postgresql. There seems to be awful lots of tutorials for MySQL+Python, but not so many for Postgresql+Python. Where should I start? I'm not very good at database things, but have written some little programs with MySQL+Python/Php/Java. So, if you have some good tutorials or something else info, I'd be glad to know! Oh, I can install additional modules, but it would be great if Ubuntu had them... Thanks! -- Olli Rajala <>< Tampere, Finland http://www.students.tut.fi/~rajala37/ "In theory, Theory and Practice should be the same. But in practice, they aren't." - Murphy's Proverbs

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What does Python gain by having immutable types?
by Tony C Nov. 15, 2005

Nov. 15, 2005

A friend recently asked my this didn't modify his original string variable s1="this is a string" s1.replace("is a", "is a short") "this is a short string" print s1 "this is a string" After showing him to change it to this s1 = s1.replace("is a", "is a short") print s1 "this is a short string" He then asked Why is it that the sort operation modfies the original list variable? l1=[] l1.append(3) l1.append(44) l1.append(1) l1.append(22) l1 [3, 44, 1, 22] l1.sort() l1 [1, 3, 22, 44] I don't know, but I think it has something to do with strings being immutable, whiles lists are mutable. So, other than the non-informative answer " because that's how the language was written" are there any other reasons how Python benefits from immutable types? Does it really matter if s1 is a different object, so long as it contains the expected modified string? The list variable is the same object, and contains the sorted list, so why bother with the complexity of immutable types at all?

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Program to lock folders under win32
by Mark Kels Sept. 4, 2005

Sept. 4, 2005

Hi list. I want to make a program to lock folders (so the user can only access them if he knows the password) under win32, the only problem is that I have no idea how to start or what to do. Do you guys have any ideas of how to do it? Thanks! -- 1. The day Microsoft makes something that doesn't suck is probably the day they start making vacuum cleaners. 2. Unix is user friendly - it's just picky about it's friends. 3. Documentation is like sex: when it is good, it is very, very good. And when it is bad, it is better than nothing. - Dick Brandon

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IDLE not working?
by Jeff Peery Aug. 5, 2005

Aug. 5, 2005

Hello, I upgraded python to 2.4 and now my IDLE isn't working. There is an error indicating something is wrong with my configuration file for the IDLE settings. Any suggestions for how to solve this problem would be much appreciated. thanks. Jeff

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wxPython shaped window
by Adam Bark July 3, 2005

July 3, 2005

On 6/26/05, Adam Cripps <kabads(a)gmail.com> wrote: > > On 6/25/05, Adam Bark <adam.jtm30(a)gmail.com> wrote: > > Thanks for the info Adam I just seem to be having a problem with the > panel > > size it greys out nearly all the image. Ideally I would like to make the > > > panel transparent but I can't work out how to do that. > > > > > > On 6/25/05, Adam Cripps <kabads(a)gmail.com> wrote: > > > On 6/25/05, Adam Bark < adam.jtm30(a)gmail.com > wrote: > > > > Is it possible to put controls into a shaped window in wxPython. I > have > > > > tried putting a button on the demo and it becomes the exact size and > > > shape > > > > of the window. Also when I tried to bind it to an action it wouldn't > > even > > > > start. > > > > > > > > Adam > > > > > > > > > > I'm working through something similar myself at the moment. > > > > > > Try adding a wx.Panel to the frame and then the button to the panel. > > > You can position them through pos parameter, but it should default to > > > the top left of the panel and have a good size if you use > > > button.SetSize(button.GetBestSize()) > > > > > > HTH > > > > > > Adam > > Adam - how much code do you have? Why not post it either here or the > wxpython-users list (to which I'm also subscribed) and we can take a > look. > > Adam > > -- > http://www.monkeez.org > PGP key: 0x7111B833 I tried posting to the wxpython-users list but I'm not sure it worked nobody replied anyway. Here's my test script: import wx class Frame(wx.Frame): def __init__(self): wx.Frame.__init__(self, None, -1, "Shaped Window", style = wx.FRAME_SHAPED | wx.SIMPLE_BORDER | wx.FRAME_NO_TASKBAR | wx.STAY_ON_TOP ) self.hasShape = False self.delta = (0,0) self.Bind(wx.EVT_PAINT, self.OnPaint) self.Bind(wx.EVT_MOTION, self.OnMouseMove) self.bkground = wx.Bitmap("/home/adam/bkgrnd.gif", wx.BITMAP_TYPE_GIF) w, h = self.bkground.GetWidth(), self.bkground.GetHeight() self.SetClientSize((w, h)) self.Bind(wx.EVT_WINDOW_CREATE, self.SetWindowShape) panel = Panel(self, w, h) panel.Show() dc = wx.ClientDC(self) dc.DrawBitmap(self.bkground, 0,0, True) def SetWindowShape(self, evt): # Use the bitmap's mask to determine the region r = wx.RegionFromBitmap(self.bkground) self.hasShape = self.SetShape(r) def OnPaint(self, event): dc = wx.PaintDC(self) dc.DrawBitmap(self.bkground, 0,0, True) def OnMouseMove(self, evt): if evt.Dragging() and evt.LeftIsDown(): x, y = self.ClientToScreen(evt.GetPosition()) fp = (x - self.delta[0], y - self.delta[1]) self.Move(fp) class Panel(wx.Panel): def __init__(self, parent, width, height): wx.Panel.__init__(self, parent, -1, size=(width, height)) button = wx.Button(self, -1, "hello") button.SetSize(button.GetBestSize()) self.SetSize((width, height)) #print dir(self) if __name__ == "__main__": app = wx.PySimpleApp() frame = Frame() frame.Show() app.MainLoop() Thanks. Adam.

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slicing nested lists/dicts/tuples
by Luis N July 2, 2005

July 2, 2005

Hi, >>> l [{'last': 'Bar', 'first': 'Foo'}, {'last': 'Bar', 'first': 'Foo'}, {'last': 'Bar', 'first': 'Foo'}, {'last': 'Bar', 'first': 'Foo'}] This is how I imagine it: for i in l: for j in l[i]: for k in l[i][j]: print k.get('first') print k.get('last') Is there a short and sweet way of doing this (that actually works). Luis.

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Re: [Tutor] Alternative File I/O for Tuples (fwd)
by Danny Yoo July 2, 2005

July 2, 2005

---------- Forwarded message ---------- Date: Sun, 26 Jun 2005 14:29:22 -0400 From: Don Parris <webdev(a)matheteuo.org> To: Danny Yoo <dyoo(a)hkn.eecs.berkeley.edu> Subject: Re: [Tutor] Alternative File I/O for Tuples On Sat, 25 Jun 2005 22:52:08 -0700 (PDT) Danny Yoo <dyoo(a)hkn.eecs.berkeley.edu> wrote: > > > > In your example, it looks like every row is ten characters long. A > ^^^ > Hi Don, > > Gaa, that's why I'm so bad at matrix math. I meant "column", not "row". > Sorry about that. I guess I should have used a different example - some names are longer than others. Williams is shorter than Vandenbosch, for example. So the columns will need to be formatted appropriately. I'll play with this a bit. I should also have said that I need to work primarily with GNU/Linux - printing with Windows can come a little later. Kent is kind of on track. I let the user view the report on the console screen (nice to verify what you're about to print), and then give them the choice of printing it, or returning to the menu for other tasks. For instance, they may simply want to look up a number, not print out the phone list. ### Print or Return to Menu ### if whatNext == 'p': os.system("lpr mbrPhone.txt") # prints the pickled file. elif whatNext == 'r': pass # BTW, is this a good use of "pass"? The screen print out is as it should be - nice, neat columns. So, instead of this: print 'Phone List' for record in Results: print '%s\t%s\t%s' % record # prints to screen mbrPhone = open('mbrPhone.txt', 'w') cPickle.dump(Results, mbrPhone) # pickles the data into a file mbrPhone.close() I tried this: mbrPhone = open('mbrPhone.txt', 'w') mbrPhone.writelines(repr(Results)) mbrPhone.close() Which produces this in the text file: (('Everybody', 'Anonymous', None), ('James', 'Austin', '704-111-1234'), ('Janet', 'Austin', '704-111-1234'), ('James', 'Austin', '704-111-1234'), This is an improvement over pickling the data into a file. Still, it's not quite the columnar layout I'd like to achieve. I'll try that recipe that was suggested to see if I can get it working with files. If it's the one I'm thinking of, it offers a fantastic layout ('bout as good as it gets with ASCII text) for printing out to screen. I guess I'm asking two closely-related questions: (1) how to format the file so it can be readable, and (2) how to send that file to the printer. I used os.system('lpr, filename') above. Is there another way? Don -- evangelinux GNU Evangelist http://matheteuo.org/ http://chaddb.sourceforge.net/ "Free software is like God's love - you can share it with anyone anytime anywhere."

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A more Pythonic way to do this
by D. Hartley July 1, 2005

July 1, 2005

Hey guys! I have a 'quest,' and at first glance this email looks long, but the problem is probably not as complex as the length implies. Please bear with me, if I could get some advice on this particular problem, it would go along way toward helping me be a better Python programmer. Some of you might remember, a few months ago, I was working on a space invaders game for a birthday present. One of the functions I really wanted to add to the game was to change the enemy "ships" at each new level. Because of my deadline and my newness to Python, I did this in an extremely ugly way. To give you an idea: the original main loop called: enemyship_sprites = createEnemies(screen, enemy_speed) createEnemies looks like this: def createEnemies(screen, speed): enemyship_sprites = EnemySprites(speed) for rows in xrange(5): for cols in xrange(8): enemyship_sprites.add(Enemy((cols*60)+20, (rows*40)+30), level) enemyship_sprites.draw(screen) return enemyship_sprites It creates an instance of EnemySprites (my holder class) which contains code for when the ships hit bottom, when to update them, etc. It also calls "Enemy()", which looks like this: class Enemy(pygame.sprite.Sprite): def __init__(self, startx, starty): pygame.sprite.Sprite.__init__(self) if level == 1: self.image, self.rect = load_image('salad_ship.bmp', -1) self.rect.centerx = startx self.rect.centery = starty def update(self, direction, go_down): jump = 40 # how much the enemies move to the right/left on each jump if go_down: # if a ship is moving down on this round, # it doesn't move on the x-axys self.rect.move_ip((0, 5)) else: # move a ship in the x-axys. # if direction=1, it moves to the right; -1 to the left self.rect.move_ip((jump * direction, 0)) # maybe it's time for a shot? :) # the chances are 1/30 dice = random.randint(0,30) global enemy_shot_sprites if dice == 1: shot = EnemyShot(self.rect.midtop) enemy_shot_sprites.add(shot) Now, get ready for one of the uglier things you've probably seen lately (!!): Since I can only access the variable "level" from within the main loop, for some reason I thought I couldnt use it in my class definitions (which of course come before and are outside of the mainloop). So within the main loop, I did: if level == 1: enemyship_sprites = createEnemies1(screen, enemy_speed) elif level == 2: enemyship_sprites = createEnemies2(screen, enemy_speed) elif level == 3: enemyship_sprites = createEnemies3(screen, enemy_speed) elif level == 4: enemyship_sprites = createEnemies4(screen, enemy_speed) elif level == 5: enemyship_sprites = createEnemies5(screen, enemy_speed) elif level == 6: enemyship_sprites = createEnemies6(screen, enemy_speed) elif level == 7: enemyship_sprites = createEnemies7(screen, enemy_speed) elif level == 8: enemyship_sprites = createEnemies8(screen, enemy_speed) else: enemyship_sprites = createEnemies9(screen, enemy_speed) And yes, I created 9 different createEnemies, all pretty much carbon copies of each other except that they called Enemy1, Enemy2, Enemy3, etc. And then (you guessed it), I created 9 different Enemy functions, too, so that each one could have its own (different) bitmap. Now... this is just ridiculous. To my credit, I did actually know that at the time. But the day before the birthday, I figured if I could make it work somehow, I would, and I'd make it prettier later. Now just happens to be that later ;) So now that I've got a little more Python experience under my belt (not much, but a little), it occurred to me that when I call createEnemies in the mainloop, I could pass in an argument 'level'. mainloop now starting off with: enemyship_sprites = createEnemies(screen, enemy_speed, level) level is one of my main loop variables, so it'll know what i'm talking about and can take that variable and pass it in when it calls createEnemies. (Btw, please forgive me if I mix up terms like argument and variable or use them in the wrong places, I'm still getting used to them!) In any case, then I changed my createEnemies to look like this: def createEnemies(screen, speed, level): enemyship_sprites = EnemySprites(speed) for rows in xrange(5): for cols in xrange(8): enemyship_sprites.add(Enemy((cols*60)+20, (rows*40)+30), level) enemyship_sprites.draw(screen) return enemyship_sprites Since the part that changes each level actually matters when the Enemy function gets called (because that's where the bmps are loaded), I made Enemy need 'level': class Enemy(pygame.sprite.Sprite): def __init__(self, startx, starty, level): pygame.sprite.Sprite.__init__(self) if level == 1: self.image, self.rect = load_image('salad_ship.bmp', -1) elif level == 2: (.................etc) self.rect.centerx = startx self.rect.centery = starty (...............etc) Now I know this email is getting hard to read ;) At this point I was thinking I'd have one createEnemies, called in the mainloop, which would take the level and, when it called Enemy to create the ships, use that level argument to determine which bmp to use for the ship itself. One createEnemies(), one Enemy(), there you go. But now it's giving me an error when createEnemies is called, for the enemyship_sprites.add(Enemy((cols*60)+20, (rows*40)+30), level) line, saying __init__() (and this would be Enemy's init, correct?) takes exactly 4 arguments (3 given): and Enemy's init, as you can see, takes (self, startx, starty, level). But the first argument is just 'self'! I don't have to pass that in.... I never *did*, anyway, in all my Enemy1, Enemy2, Enemy3 code...? I can send the full code for anybody who thinks that would be clearer to look at (ha ha) - I was going to attach it here but it would make the message too big for the list. I know that going through such a messy problem like this is a pain, and questions like this don't always get a lot of responses on the list. My code worked, it was just messy, and so I suppose I could just leave it alone. But I want to clean it up: I want to make it more Pythonic, more organized, more efficient, and would really love any advice anyone could offer. Heck, for all I know, I could just be needing to add a "self.___" somewhere, heaven knows that has tripped me up before! Would love to hear from you guys, and thanks again, Denise

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would pickle or cpickle help?
by Ertl, John July 1, 2005

July 1, 2005

All, I have a text file that contains several thousand lines of space delimited text that contain a ship ID and a ship name. This file is updated every few months. I have another file that contains the ship ID and some other info but not the ship name. I have to append the ship name to the end of the line. Easy enough. I currently make a dictionary of the shipID(key) and ship name(value) and use this to append the ship name to the end of the line that contains the ship ID. Could I use something like cpickle to store the dictionary once it is made so I would not have to make it each time? I have never tried to use pickle so I am bit fuzzy on what it can store and what it can't. Also would it really buy me anything...it only takes a second or two to make the dictionary? There is a chance the file that I use to make the dictionary will eventually grow to be 10,000 lines or more. Thanks for the ideas. John Ertl

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{Possible Spam?} Need help new to Programming
by Jimmy July 1, 2005

July 1, 2005

My project right now is "Write another program that reads 100 numbers from the user and prints out the sum" Now I can get the program to do these functions, but it won't stop even using the break statement. Any help or guidance would be great.

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