🌐 Mailman 3 April 2001 - Tutor - python.org

Windons Task tray
by rhicks＠rma.edu July 4, 2001

July 4, 2001

Is it possible to minimize a python program to the task tray area of the taskbar in Windows95/98? Bob pop3.rma.edu

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software design
by Katharine Stoner May 11, 2001

May 11, 2001

Hi all, Does anyone know of a good scource on how to design programs before you start programming? -Cameron Stoner

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determining whether a set is a group
by Julieta May 1, 2001

May 1, 2001

Hello everyone! I took a modern abstract algebra class this semester and there is something that caught my attention, and which I think would make a neat program. I would like to have a program in which given any set and the table accompaning the set, the computer would display a message stating whether the set is a group or not. I guess I would have to get the computer to ask for the amount of elements in the set, say 6, and then have the computer generate a 6 by 6 matrix, in which the user would enter the corresponding table, so the computer can figure out, after testing for the required properties, whether the set is a group or not. You might think that I'm very lazy to want the computer to do this for me, and I guess you are right, this is probably the reason why computer programming is becoming more interesting by the minute. You do the work only once and then the computer does it for you. It is beautiful! I have so many little projects that could make my life much much easier, that I don't know where to start. My only and biggest problem is that I'm a computer illiterate and have no clue as to where to start, however, I'm willing to do what it takes to learn. I know that some help over the internet might not do miracles for me, but I guess it would be a start. I have the book Teach Yourself Python in 24 Hours and I'm reading it, but I guess I need more help. Can you help me. Julieta

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Program not accessing while loops
by Aaron May 1, 2001

May 1, 2001

Hi, I wrote this out last night on a different computer and I had the script running fine but now that I rewrote it doesn't seem to be accesing the second group of while loops, the main menu will load and keep running and asking for input, but it won't call on the loop. #character managment program totop = 1 while totop == 1: print print "Main Menu" print "---------" print mainmenu = ["1 for to create a new character", "2 to manage an existing character", "3 to exit the program"] for x in mainmenu: print "Enter", x mainmen = raw_input(">") while mainmen == 1: print "This function is under construction" while mainmen == 2: print "This function is under construction" while mainmen == 3: exit = raw_input("are you sure? ") if exit == r"yes": totop == 2 break elif exit == r"no": totop == 1 break while mainmen < 3: print "Invalid choice, choose again" for x in mainmenu: print "Enter", x mainmen = raw_input(">") Thanks, aaron

2 1

deciphering code
by Julieta Rangel May 1, 2001

May 1, 2001

Can anyone help me decipher the following code? I know it is to create a polynomial and calculate its derivative, but I would like to know what the lines do, in other words, figure out the purpose for those lines. import string class Poly: def __init__ ( self, v = 'x', c = [0]): """__init__(): Initializes a polynomial Default variable is x Default polynomial is zero""" self.var = v self.coef = c self.deg = len(c)-1 def __str__ (self): """__str__(): Converts a polynomial into a string""" x = `self.coef[0]` for i in range (1, self.deg+1): x = x + " + " + `self.coef[i]` + self.var + "^" + `i` return x def Derivative(p): """Input: an instance of a polynomial Output: a polynomial that is the derivative of the input polynomial Side Effects: None""" pv=p.var pc=[] if p.deg==0: return Poly (v=pv,c=[0]) else: for i in range(0,p.deg): d=(i+1)*p.coef[i+1] pc.append(d) return Poly (v=pv,c=pc) **************************************************************** I'll appreciate any kind of help. Also, what modifications should I make to this code so that a user can input a polynomial and the computer calculates the derivative and displays the answer? Julieta _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com

2 1

Displaying image in scrolled canvas
by kromag＠nsacom.net April 30, 2001

April 30, 2001

I am attempting to place a large .gif file into a scrolled canvas. I am working from the examples in programming python (in case the code looked slightly familiar :-) To wit: from Tkinter import * class ScrolledCanvas(Frame): def __init__(self, parent=None, color='white'): Frame.__init__(self, parent) self.pack(expand=YES, fill=BOTH) photo=PhotoImage(file='\windows\desktop\wacky3.gif') canv = Canvas(self, bg=color, relief=SUNKEN) canv.config(width=1010, height=745) canv.config(scrollregion=(0,0,300, 1000)) canv.create_image(10,10, image=photo, anchor=NW) sbar = Scrollbar(self) sbar.config(command=canv.yview) canv.config(yscrollcommand=sbar.set) sbar.pack(side=RIGHT, fill=Y) canv.pack(side=LEFT, expand=YES, fill=BOTH) if __name__ == '__main__': ScrolledCanvas().mainloop() results in the properly-sized frame and scrollbar, but for some reason the image does not pop to life. What am I missing here? d

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Breaking threads
by kromag＠nsacom.net April 30, 2001

April 30, 2001

Howdy, I am working my way through "Programming Python" from the begining (I have asked too many silly questions! :-). Here is a non-silly question: When I run the following: ----------begin stuff------------------------------ import thread, time glarf=open('\windows\desktop\goat.txt', 'w') def counter(myId, count): for i in range(count): mutex.acquire() # time.sleep(1) glarf.write('[%s]=> %s' % (myId, i)) mutex.release() mutex = thread.allocate_lock() for i in range(10000): thread.start_new_thread(counter, (i, 3)) time.sleep(6) print "Your greasy granny's got holes in her panties. And your main thread is exiting...." --------end stuff--------------- It starts to write 10,000 counts to goat.txt, then dies with the following: Traceback (most recent call last): File "cornfedbeef.py", line 14, in ? thread.start_new_thread(counter, (i, 3)) thread.error: can't start new thread It works fine in iterations of 10, 100 and 1000. Why does it puke at the 10000 mark? Wow! d

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RE: [Tutor] 15 puzzle
by alan.gauld＠bt.com April 30, 2001

April 30, 2001

This may well have been answered already - I'm catching up from a week's vacation... It appears not yet... Here is a skeleton for a 3x3 game and lacks any input validation - ie it's easily broken but it should form a basis for something... Here it is in full 4x4 size with minimal error detection... class Grid: size = 4 grid = [(0,1),(1,2),(2,5),(3,9), (4,3),(5,7),(6,6),(7,10), (8,0),(9,4),(10,8),(11,11), (12,15),(13,14),(14,13),(15,12) ] def findBlock(self,val): if val in range(self.size**2): for item in self.grid: if item[1] == val: return item else: print "invalid item" return self.findBlock(0) def printIt(self): for i in self.grid: if (i[0]+1)%self.size != 0: print i[1], else: print i[1] def isSorted(self): limit = (self.size**2)-2 for i in range(limit): if (self.grid[i+1][1] - self.grid[i][1]) != 1: return 0 return 1 def swap(self,pos): gap = self.findBlock(0) self.grid[gap[0]] = (gap[0],pos[1]) self.grid[pos[0]] = (pos[0],0) g = Grid() g.printIt() while not g.isSorted(): block = input("Item to move?") item = g.findBlock(block) g.swap(item) g.printIt() if g.isSorted(): print "Game over" break

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RE: [Tutor] Multiplication of polynomials
by alan.gauld＠bt.com April 30, 2001

April 30, 2001

how illiterate I am at computer programming, this is what I would do: I Pretty much correct. But instead of using lists try using dictionaries. Thus the dictionary vcan be keyed by the order of the polynomial and you can assign the coefficients to the value part. This makes rationalising the final expression a bit easier IMHO. (In fact you could do it 'on the fly') Alan G.

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RE: [Tutor] 15 puzzle
by alan.gauld＠bt.com April 30, 2001

April 30, 2001

This may well have been answered already - I'm catching up from a week's vacation... Here is a skeleton for a 3x3 game and lacks any input validation - ie it's easily broken but it should form a basis for something... Alan G class Grid: grid = [(0,1),(1,2),(2,5), (3,3),(4,7),(5,6), (6,0),(7,4),(8,8)] def findBlock(self,val): for item in self.grid: if item[1] == val: return item def printIt(self): for i in self.grid: if (i[0]+1)%3 != 0: print i[1], else: print i[1] def isSorted(self): for i in range(7): if self.grid[i][1] > self.grid[i+1][1]: return 0 return 1 def swap(self,pos): gap = self.findBlock(0) self.grid[gap[0]] = (gap[0],pos[1]) self.grid[pos[0]] = (pos[0],0) g = Grid() g.printIt() while not g.isSorted(): block = input("Item to move?") item = g.findBlock(block) g.swap(item) g.printIt() if g.isSorted(): print "Game over" break

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