🌐 Mailman 3 August 2002 - Tutor - python.org

Backslashes inside of variable
by Phoebus Nov. 23, 2003

Nov. 23, 2003

I am running Python 2.2 on Win2k. I have a program which writes a filename, with backslashes to a file, along with other stuff. I read the file in using readlines() and put each line into a variable. My problem is I want to use the filename, but I can't use it because of the backslashes. I know about doing open(r"d:\test\file.txt","w") or even open(`d:\test\file.txt`,"w"), but the filename is inside of a variable so when I do open(filename,'w'), I have problems. Can anyone help? Thanks, Steve --

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FW: Embedding Python
by BELSEY, Dylan Dec. 4, 2002

Dec. 4, 2002

Hi Tutor list, I posted the below mail last week and haven't seen any replies on the topic so I am not sure if it got through or if the questions were out of the scope of this list. If it is out of scope, any suggestions to what list would be more appropriate. Further to the information provided, I compiled the code in "Release" mode and still obtained the same error. When I refer to error I mean the 'import site' failure message. I would appreciate any help on this. Thanks, Dylan > -----Original Message----- > From: BELSEY, Dylan > Sent: Wednesday, 24 July 2002 15:51 > To: tutor(a)python.org > Subject: Embedding Python > > Hi, > I am attempting to try and get the embedding of Python running on my > system (WinNT). I am using VC++ and I copied the code from "5.1 Very High > Level Embedding" within "Extending and Embedding the Python Interpreter" > from the Python docs. I have also installed the latest release of Python, > version 2.3a0. The code from the documentation is pasted below: > > #include <Python.h> > > int > main(int argc, char *argv[]) > { > Py_Initialize(); > PyRun_SimpleString("from time import time,ctime\n" > "print 'Today is',ctime(time())\n"); > Py_Finalize(); > return 0; > } > > It compiles OK but when I go to run it I get the following error: > > 'import site' failed; use -v for traceback > Today is Wed Jul 24 15:39:04 2002 > Press any key to continue > > Any ideas why this error is occurring. Has anyone seen this error > and if so why is it occurring? The code is compiled in debug mode so > maybe the error is an artefact of that?? I have noticed that when I put > the produced executable in the directory where python.exe lives I don't > get the error. Unfortunately I don't know enough about the guts of Python > to follow this discovery through. > Any help would be appreciated. > Dylan

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Planning out your program
by Britt A. Green Sept. 14, 2002

Sept. 14, 2002

I made a very crude little text adventure in Python a few months ago. However, as I began to add on functionality to it, it became apparent that a lot of the underlying code wasn't capable of being improved. The original code basically let one player walk amongst a dozen rooms and pick things up. To get it to do much more would mean a huge rewrite of what I'd already done. So I'm going to have a lot of free time this summer and want to write something a bit more complex. What would be the best way to plan out my code before I start writing? Britt -- "My mom says I'm cool."

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text module
by Kyle Babich Sept. 2, 2002

Sept. 2, 2002

I've seen a few people write to this list with questions on how to count words, lines, etc. from a file. So based on this last night I started to write a module (called it the text module, any better ideas?) that will do all of this. Before I got to far into this I thought I would ask people opinions on this idea and what I have so far. First of all I would appeciate it if you could test what I have so far. Here is the source (text.py): #################### import string def WordCount(location): subj = file(location, "r") body = subj.readlines() subj.close() items = [] words = 0 for each in body: items.append(string.strip(each)) items = string.join(items, " ") for each in items.split(" "): words = words + 1 print words def CharCount(location, spaces): subj = file(location, "r") body = subj.readlines() subj.close() items = [] chars = 0 if spaces == 0: for each in body: items.append(string.strip(each)) items = string.join(items, " ") items = string.replace(items, " ", "") for each in items: chars = chars + 1 print chars elif spaces == "0": for each in body: items.append(string.strip(each)) items = string.join(items, " ") items = string.replace(items, " ", "") for each in items: chars = chars + 1 print chars elif spaces == 1: for each in body: items.append(string.strip(each)) items = string.join(items, " ") for each in items: chars = chars + 1 print chars elif spaces == "1": for each in body: items.append(string.strip(each)) items = string.join(items, " ") for each in items: chars = chars + 1 print chars def LineCount(location): subj = file(location, "r") body = subj.readlines() subj.close() lines = 0 for each in body: lines = lines + 1 print lines #################### What it does: WordCount(location) counts all words (seperated by spaces). It works like WordCount("c:\\windows\\desktop\\testfile.txt") and returns a number. LineCount(location) works the same way and counts lines seperated with a \n. CharCount(location, spaces) works in a similar way, but if you enter a 0 for spaces \n and spaces will not be counts as characters and if you enter 1 they will be. Note: the string module is required to run WordCount() and CharCount() Any suugestions, ideas? Do you think that a module like this (assuming I continue development on it, I mean it's not even 24 hours old) will ever get anywhere? Thank you, -- Kyle

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q about method(self)
by Erik Price Sept. 2, 2002

Sept. 2, 2002

A class method generally takes "self" as its first argument. I had been wondering for some time why this is, since it seems redundant if it's there for all class methods. But I just realized -- you can call an object's method without using dot notation in Python, like this: method(instance_reference, args) rather than only like this: instance_reference.method(args) I didn't realize that until just now. But what I'm wondering is, why/when would you want to use this form? Is it just an aesthetic thing, or is it something that is required b/c of the way that Python handles user-defined classes and objects? Or something else? One other quickie question -- not that I would ever need to do this, but could a different identifier other than "self" ever be used? (such as "this") It -appears- that "self" is just a reference within a class, but perhaps there's magic going on that I don't know about. Thanks, Erik -- Erik Price email: erikprice(a)mac.com jabber: erikprice(a)jabber.org

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returning to my memberlister script
by Kirk Bailey Sept. 1, 2002

Sept. 1, 2002

Well, I have been busy, but finally got to return to my memberlister script. It gets this result in the www.errorlog: SyntaxError: invalid syntax [Thu Aug 29 00:26:38 2002] [error] [client 63.208.207.252] Premature end of script headers: /www/www.tinylist.org/cgi-bin/TLmemberlister.py Traceback (innermost last): File "/www/www.tinylist.org/cgi-bin/TLmemberlister.py", line 126, in ? print 'listname='+mylist+'' TypeError: __add__ nor __radd__ defined for these operands Here is the script ( I will omit the text headers): login as: howlermo Sent username "howlermo" howlermo(a)howlermonkey.net's password: Last login: Wed Aug 28 00:04:44 2002 from dialup-65.59.82. Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994 The Regents of the University of California. All rights reserved. FreeBSD 3.4-RELEASE (HOWLER) #0: Thu Jun 21 22:13:44 EDT 2001 Welcome to the Monkey! Please, enjoy your stay... now get to work! You have new mail. $ /www/www.howlermonkey.net /www/www.howlermonkey.net: permission denied $ ls TL*.* ls: TL*.*: No such file or directory $ ls TL*.* ls: TL*.*: No such file or directory $ pwd /usr/home/howlermo $ cd /www/www.howlermonkey.net UW PICO(tm) 3.7 File: testlist3.owner UW PICO(tm) 3.7 File: TLmemberlister.py UW PICO(tm) 3.7 File: TLmemberlister.py Modified print '' print '</STYLE>' print "</head>" print '<body bgcolor="FFFFFF" text="000000" ><blockquote>' print '   TinyList' print '<hr width=50%>' # form=cgi.FieldStorage() # recover the form's data, if not (form.has_key("Owner")): print "Key 'owner' not found!" #120 if not (form.has_key("password")): print "key 'password' not found!" if not (form.has_key("listname")): print "key 'listname' not found!" mylist = form["listname"] # listname, print 'listname='+mylist+'' # myowner = form["Owner"] # owner, print 'owner='+myowner+'' # mypassword = form["password"] # and password. print 'password='+mypassword+'' #130 f1=open('/lists/' + listname + '.owner','r') # read the (listname).owner file, trueowner=string.srip(f1.readline()) # read the owner id trueword=string.strip(f1.readline()) # read THE PASSWORD f1.close() # Close the file. if myowner == trueowner : # if the owner matches up, test the password; if mypassword==trueword: # if the password also matches, f1=open('/lists/'+ mylist,'r') #proceed to access the member roster. members=f1.readlines() # read them in, f1.close # and close the file. for i in members: #130 print i + ' ' else: print 'Sorry, wrong password.' else: print 'Sorry, wrong owner id.' # print '<hr width=50%></body></html>' # close the page, and end. # # #140 # ns# Note I am using 1.5.2 python, and an upgrade is not practical at this time. I invite suggestions, advice, evil humor, and dead parrot sketch sequals. -- end Respectfully, Kirk D Bailey +---------------------"Thou Art Free." -Eris-----------------------+ | http://www.howlermonkey.net mailto:highprimate@howlermonkey.net | | KILL spam dead! http://www.scambusters.org/stopspam/#Pledge | | http://www.tinylist.org +--------+ mailto:grumpy@tinylist.org | +------------------Thinking| NORMAL |Thinking----------------------+ +--------+ ------------------------------------------- Introducing NetZero Long Distance Unlimited Long Distance only $29.95/ month! Sign Up Today! www.netzerolongdistance.com

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A simple RPN calculator
by Scot W. Stevenson Sept. 1, 2002

Sept. 1, 2002

Hello there, I had started a thread about Reverse Polish Notation calculators a while ago, and Gregor actually wrote one, and I did that smart-ass thing of coming back and saying, hey, really neat, Gregor, but how about the following functions...So I guess I owe him some code =8). Included is my attempt at a simple RPN calculator, any feedback of course would be most appreciated. Y, Scot ============================================================ #!/usr/bin/env python # Simple Reverse Polish Notation Calculator # Scot W. Stevenson 28. August 2002 # For the Python Tutor Mailinglist import cmd, sys class rpn_calc(cmd.Cmd): """Simple RPN calculator""" def __init__(self, stacksize=4): self.stack = [0]*stacksize self.stacksize = len(self.stack) self.lastregister = self.stacksize-1 self.intro='Simple RPN Calculator\nScot W. Stevenson 28. Aug 2002' self.lastx = 0 self.operations = { '+': self.do_add, '-': self.do_subtract, '*': self.do_multiply, '/': self.do_divide, '^': self.do_power} # Helper functions def _stacklift(self, new_x): """Lift stack by one entry, last register is lost""" del self.stack[self.lastregister] self.stack.insert(0, new_x) def _stackdrop(self, new_x): """Drop stack by one entry, losing Y register entry, last register is doubled""" self.stack.append(self.stack[self.lastregister]) del self.stack[0] self.stack[0]=new_x # Catch numbers and operators def default(self, entry): """Catch numbers and operators and process them. If entry is neither number nor operator, ignore and pass on to cmd loop.""" # Catch numbers try: number = float(entry) self.lastx = self.stack[0] self._stacklift(number) except ValueError: pass # Catch operations if entry in self.operations: operation = self.operations[entry] operation() # Show X register after each command def postcmd(self, *dummy): """Display the contents of the X register after each command""" print " %f" % self.stack[0] # Calculator commands def do_add(self, dummy=None): result = self.stack[1] + self.stack[0] self._stackdrop(result) def do_clrx(self, rest): """Clear X register""" self.stack[0] = 0 def do_divide(self, dummy=None): try: result = self.stack[2] / self.stack[0] self._stackdrop(result) except ZeroDivisionError: print "*** Division by Zero Error ***" def do_enter(self, dummy): """Perform a stack lift; last register value is lost, first (X) register value is pushed into the second (Y) register""" self._stacklift(self.stack[0]) def emptyline(self, dummy=None): """An empty line is treated like hitting the ENTER key""" self.do_enter(None) def do_lastx(self, dummy): """Restore X register value from before the operation in the X register, performing a stack lift""" self._stacklift(self.lastx) def do_multiply(self, dummy=None): try: result = self.stack[1] * self.stack[0] self._stackdrop(result) except OverflowError: print '*** Overflow Error ***' def do_power(self, dummy=None): try: result = pow(self.stack[1], self.stack[0]) self._stackdrop(result) except OverflowError: print '*** Overflow Error ***' def do_print(self, rest): """Print stack. Mostly used for debugging""" for i in range(self.stacksize-1, -1, -1): print 'Reg %s: %f' % (i, self.stack[i]) def do_quit(self, dummy): sys.exit() def do_rdown(self, dummy): """Roll down stack""" self.stack.append(self.stack[0]) del self.stack[0] def do_rup(self, dummy): """Roll up stack""" self.stack.insert(0, self.stack[self.lastregister]) del self.stack[self.lastregister+1] def do_subtract(self, dummy=None): result = self.stack[1] - self.stack[0] self._stackdrop(result) def do_xy(self, dummy): """Swap X and Y registers""" self.stack[0], self.stack[1] = self.stack[1], self.stack[0] # Help texts def help_add(self): print 'Add X and Y register. Use "+" key or "add" command' def help_clrx(self): print 'Clear X register' def help_divide(self): print 'Divide X by Y register. Use "/" key or "divide" command' def help_enter(self): print 'Push stack up by one, last register is lost' def help_help(self): print 'Prints list of commands' def help_lastx(self): print 'Retrieves value of the X register from before the last' print 'operation and pushes it in the X register, lifting the' print 'stack.' def help_multiply(self): print 'Multiply X by Y register. Use "*" key or "subtract" command' def help_power(self): print 'Take Y to the Xth power. Use "^" key or "power" command' def help_print(self): print 'Print stack. Used mostly for debugging' def help_rdown(self): print 'Rolls stack downwards' def help_rup(self): print 'Rolls stack upwards' def help_quit(self): print 'Quit program' def help_subtract(self): print 'Subtract X from Y register. Use "-" key or "subtract" cmd' def help_xy(self): print 'Swaps X and Y registers' # Main loop if __name__ == '__main__': testcalc = rpn_calc() testcalc.cmdloop()

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help required
by hotmail Sept. 1, 2002

Sept. 1, 2002

i was wondering if it is possible to make a gui for python programs to make the use of them easier and also i was wondering if it si possible to out put images as well as text in programs. thanks for any help in advance

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Re: [Tutor] Re: q about method(self)
by Stephen Harris Aug. 31, 2002

Aug. 31, 2002

"Emile van Sebille" <emile(a)fenx.com> wrote in message news:akqqpg$obt$1@main.gmane.org... > Erik: > > A class method generally takes "self" as its first argument. > > It is named self by convention only. You can call it 'this' if you want. > > > I had > > been wondering for some time why this is, since it seems redundant if > > it's there for all class methods. But I just realized -- you can call > > an object's method without using dot notation in Python, like this: > > > > method(instance_reference, args) > > This might also be seen as function(inst_ref, args) which serves to show > that a class method is not really much different from any function. In this > case, the instance being passed could come from any class. > > > > > rather than only like this: > > > > instance_reference.method(args) > > > > I didn't realize that until just now. But what I'm wondering is, > > why/when would you want to use this form? Since I was just reading about this in the Sams Teach yourself Python in 24 Hours, which is introductory, obviously, I post: "Although you can call a function or method and use the return value to assign to or create a variable, the function itself cannot create something outside its box—unless the function uses the self parameter. We see how that's done in Listing 10.1. The way to create variables (members in OOP talk) in an object is the same way Python creates all variables—by assigning a value to them. That's what is going on Listing 10.1; self.t, self.year, self.month, and so on are variables being created as members of class now. The localtime() function returns a 9-tuple; an assignment such as that shown in the previous listing unpacks the tuple, placing the values into the variables on the left side of the = sign, exactly the way you would expect. Dow stands for ''day of the week," doy indicates "day number of the year," and dst is 1 if daylight savings time is being observed, 0 if not. After you create an instance of class now, you can, outside the box, look inside the instance and see that the __init__() method has created variables. You can inspect the variables, you can modify them, you can add new methods, and you can call any methods that are inside the class; you can even modify the methods and variables after creating an instance. However, if you do that, when you create another instance, your added methods and variables won't show up in the new instance. (There is a way to do this, but it's not something you'll be wanting to do for a long time, and it won't be covered in this book.) As you saw in the original listing for class now, which was presented in the preceding chapter (see Listing 9.2), creating an instance of a class is easy: n = now() print "The year is", n.year You may notice that creating an instance of a class looks very much like calling a function. That's because it is; Python does a few magic tricks behind the scenes, by fabricating a generic object and then passing that as the self argument to a function call that effectively looks like n = now.__init__(object) After you've created an instance of a class, you might think that you could call the class's __init__() method directly, like this: n = now() o = now.__init__(n) print "year", o.year, n is o If you run the preceding code, you'll see that you get an AttributeError that tells you that the object o is not an instance of class now, but a None object. That's because the self argument you provided to __init__() was not really a reference to itself. Only Python can construct a generic object that will really work in such a call. Chalk it up to magic." SH: I'm not sure what that last paragraph means. Regards, Stephen

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Getting Python to work...
by Robert.Simons＠us.pilkington.com Aug. 31, 2002

Aug. 31, 2002

Hi to all you programming gurus... I have downloaded to a Win98 box: Python 2.2.1 (said most stable) WxPython 2.2.3.1 - python.exe Boa.constructor 0.1.0 -alpha.win32.exe All the downloads were "runnable" so I ran them. Python 2.2.1 looks like it ran and installed (did not require a reboot. Hmmmmm) WxPython, finally required a reboot. Placed the pertinate files inside the python22 folder then it did a proper install I think. Ran the boa and it expanded into the wxPython tools sub directory. I cannot run the Boa program... I cannot get a 2.2.1 python window to run an 1.5 version program. I am using odbc and the wxPython should register it, but the simple program I am trying to run claims no knowledge of the ODBC. I attach the code from the project maybe you can tell me exactly what I am doing wrong, but feel free to help me fininsh? The installation. TIA <<pgs.py>> Rob ____________________________________________________________________________ This message and any attachments are confidential, for the exclusive use of the addressee and may be legally privileged. Any other distribution, use or reproduction is unauthorized and prohibited. If you have received this message in error, please notify the sender immediately and delete the message from your system. Visit our internet site at http://www.pilkington.com

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