🌐 Mailman 3 October 2011 - Tutor - python.org

Wave module
by Alex Krycek Feb. 12, 2015

Feb. 12, 2015

Hello, I'm trying to join two .wav files with the wave module. But when I try to use wave.open(filename, "rb") I receive the following error: Traceback (most recent call last): File "<stdin>", line 1, in <module> File "F:\PortablePython1.0\lib\wave.py", line 483, in open return Wave_read(f) File "F:\PortablePython1.0\lib\wave.py", line 162, in __init__ self.initfp(f) File "F:\PortablePython1.0\lib\wave.py", line 143, in initfp self._read_fmt_chunk(chunk) File "F:\PortablePython1.0\lib\wave.py", line 264, in _read_fmt_chunk raise Error, 'unknown format: %r' % (wFormatTag,) wave.Error: unknown format: 85 I read somewhere that there are various wave formats, only some supported by Python. Is this true? If so, is there any way I can convert my wave files into a supported kind? Thanks!

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unicode help
by Marilyn Davis Nov. 14, 2012

Nov. 14, 2012

Hi, I'm still on Python 2.6 and I'm trying to work some unicode handling. I've spent some hours on this snippet of code, trying to follow PEP 0263, since the error tells me to see it. I've tried other docs too and I am still clueless. The code works, except for the comment at the end. I would be very grateful for some help. #!/usr/bin/env python '''Unicode handling for 2.6. ''' class Currency(float): def __str__(self): value = self.__class__.symbol + float.__str__(self) return value class Yen(Currency): symbol = unichr(165) class Pound(Currency): symbol = unichr(163) def main(): y = Yen(100) print unicode(y) p = Pound(100) print unicode(p) main() """ ¥100.0 £100.0 """

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Quacks like an object
by Christopher King Nov. 23, 2011

Nov. 23, 2011

Dear Tutors, I am trying to make an object, which will appear exactly like an object of my choice. It will should be impossible to tell it is not the object. This is because I am making an object that modifies it methods so that if the methods make a change to the object, it will sync those changes to a file, but I don't want it to be another object, so foreign functions will not mistake for not being the object. For example if, I used type on the object, it should return the class of the object it is trying to mimic. I have tried everything from modifying the object's get set attribute methods, to having making a new object that has get and set the same as the object except with a filter for methods, but I had no luck. In a nutshell, I want an object that walks like another object, quacks like another object, and basically is another object. Is this possible? Sincerely, Me

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Paper Rock Scissors game - User's choice not returned properly
by Joel Montes de Oca Nov. 4, 2011

Nov. 4, 2011

Hello everyone, I am having a little trouble with a block of code that isn't behaving the way I would expect. Maybe you can give me a hand and point where it is going wrong. The function that is not working correctly belongs to a Paper Rock Scissor game I am making. This particular function is responsible to: a) Get the user's choice (Paper, Rock, or Scissors) b) Return the user's choice within the variable choice to the function that called it. The function works correctly as long as the user _does not try to enter a string other than_ 'P', 'R', or 'S'. Logic: Take the user's string and put it in the variable choice. If choice is not 'P', 'R', or 'S'then pass a message to the user and call the function again. If the choice is 'P', 'R', or 'S'then return choice to where it was called from. The problem is this. When the user enters a string other than the valid ones, the if statements catches it and calls the same function again so the user can enter a valid string. But the variable choice does not get assigned the new string entered by the user, instead it is empty. I would expect if the function runs again, the variable choice would be updated to the last value given by the user. The function: ( http://dpaste.com/644857/) def UserChoice (): # The function that returns the choice from the user print 'Please select (P) for paper, (R) for Rock, or (S) for Scissors.' choice = raw_input('What is your selection?:') if choice.lower() not in ('p', 'r','s'): # Converts the user's choice to lowercase and confirms the choice is valid print 'I am sorry, you entered\'' + choice.upper() + '\' which is an invalid response. Please try again.' raw_input('Press Enter to try again.') UserChoice () # If the choice is not valid, run the function over else: return choice Output with no problems: ( http://dpaste.com/644866/) <http://dpaste.com/644866/> Welcome to the PRS game. Please select (P) for paper, (R) for Rock, or (S) for Scissors. What is your selection?: s You threw down Scissors while the computer threw down Rock LOOSE Output with problems: ( http://dpaste.com/644868/) Welcome to the PRS game. Please select (P) for paper, (R) for Rock, or (S) for Scissors. What is your selection?: L I am sorry, you entered 'L' which is an invalid response. Please try again. Press Enter to try again. Please select (P) for paper, (R) for Rock, or (S) for Scissors. What is your selection?: s You threw down None while the computer threw down Paper LOOSE Here's the full source code in case the problem is outside of the function: ( http://dpaste.com/644873/) import random # Import the random library def main (): # The main function that gets called from main() print '\nWelcome to the PRS game.\n' choice = UserChoice () # Gets the choice from the user cchoice = ComputerChoice () # Gets the choice from the computer PrintOutcome (choice, cchoice) # Passes both choices to the PrintChoice function for display return 0 def UserChoice (): # The function that returns the choice from the user print 'Please select (P) for paper, (R) for Rock, or (S) for Scissors.' choice = raw_input('What is your selection?:') if choice.lower() not in ('p', 'r','s'): # Converts the user's choice to lowercase and confirms the choice is valid print 'I am sorry, you entered\'' + choice.upper() + '\' which is an invalid response. Please try again.' raw_input('Press Enter to try again.') UserChoice () # If the choice is not valid, run the function over else: return choice def ComputerChoice (): # The function that returns the choice from the computer PRS = ['Rock', 'Paper', 'Scissors'] # A list of choices cchoice = random.choice(PRS) # Choose a random item from the list return cchoice # Return the function def PrintOutcome (UC, CC): # Function responsable to display the choices and results PRS = ['Rock', 'Paper', 'Scissors'] # Convert the letters to words if UC == 'r': UC = PRS[0] elif UC == 'p': UC = PRS[1] elif UC == 's': UC = PRS[2] print '\n\tYou threw down', UC, 'while the computer threw down', CC +'\n' # find the outcome of the game if UC == CC: print 'We have a tie, both players gain a point!' elif UC == 'Rock' and CC == 'Scissors': print 'WIN' elif UC == 'Paper' and CC == 'Rock': print 'WIN' elif UC == 'Scissors' and CC == 'Paper': print 'WIN' else: print 'LOOSE' return 0 main() I am using Python 2.7 I am running on Ubuntu 11.10 Thanks for any help -- -Joel M.

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Re: [Tutor] Tutor Digest, Vol 92, Issue 123
by Rinu Boney Nov. 1, 2011

Nov. 1, 2011

I Use Windows.I Already Know C/C++ which makes python syntax seem very easy. Maybe Setting Up Emacs With Python Will Make Me Productive. I Have Eclipse With PyDev. Why Is There Not A Pythonic Emacs? On Mon, Oct 31, 2011 at 8:23 AM, <tutor-request(a)python.org> wrote: > Send Tutor mailing list submissions to > tutor(a)python.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://mail.python.org/mailman/listinfo/tutor > or, via email, send a message with subject or body 'help' to > tutor-request(a)python.org > > You can reach the person managing the list at > tutor-owner(a)python.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Tutor digest..." > > > Today's Topics: > > 1. Setting Up Emacs (Rinu Boney) > 2. Re: Setting Up Emacs (Steven D'Aprano) > 3. Re: Setting Up Emacs (Tim Johnson) > 4. Re: Setting Up Emacs (Alan Gauld) > 5. Re: Setting Up Emacs (Tim Johnson) > 6. Re: Method to create small and simple database (Joel M.) > 7. Re: Setting Up Emacs (Bill Allen) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 30 Oct 2011 18:53:04 +0530 > From: Rinu Boney <rinu.matrix(a)gmail.com> > To: tutor(a)python.org > Subject: [Tutor] Setting Up Emacs > Message-ID: > <CAJTWV12yyOW+nB-+cEkZWFmP0f3wJKVYErZFoe1Kzctf7DhsRQ(a)mail.gmail.com > > > Content-Type: text/plain; charset="iso-8859-1" > > I am New To Python. > I Would Like To Setup Emacs As A Python IDE. > I Don't Know Anything About Emacs! > Can Someone Help Me ? > Thanks. >

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Re: [Tutor] Simple Question On A Method (in subclass)
by Dave Angel Nov. 1, 2011

Nov. 1, 2011

(please do REPLY-ALL, or at least add the mailing list to the recipient list. Otherwise, only one person will see the message. I'm forwarding it to the group with my comments added.) -------- Original Message -------- Subject: Re: [Tutor] Simple Question On A Method (in subclass) Date: Sun, 23 Oct 2011 16:53:40 -0400 From: Chris Kavanagh <ckava1(a)msn.com> Organization: Home Office To: d(a)davea.name On 10/22/2011 6:59 PM, Dave Angel wrote: > >> My question is regarding the tell methods in the subclasses,the code >> {SchoolMember.tell(self)}, in the class Teacher & Student. I just >> don't understand what this is doing? Calling the first method {def >> tell} from the parent class, I assume? There is already a print >> statement in each of the subclass {def tell} showing details, why call >> another print statement (from parent class {def tell})?? I know this >> should be simple, but I'm confused. LOL, obviously. >> >> Thank you in advance! >> >> >> <SNIP> > Welcome to the python-tutor list. We are all volunteers here, and most, > like me, ask questions as well as answering them. it's a two-way street. > > The whole point of subclassing is to share either code, data, or both. > In this example, the amount of shared data is just the name and age, and > the shared method is tell(). Because the parent knows how to 'tell' its > information, the child doesn't need to. So instead of altering the > prints in both the child classes to print name & age, you let the common > code in the parent handle it. > > It becomes more clearly a win when you have much more data, or much more > complex methods involved. But you have to start simple. > > BTW, there were some transcription errors in the email. For example, the > code as written would be using a separate line for Salary on Mrs. > Shrividya's record. And you're missing the content of the for member in > members: loop. No problem, but it might have affected our discussion. > Did you retype it all, or was it just a glitch? Presumably you know how > to copy/paste from and to a console prompt? Chris Kavanagh said: Thanks to both Alan Gauld & Dave Angel for the help!!! I'm not sure how the transcrption errors happened, I copied & pasted. Must have not copied the entire thing. I'll correct it below. Speaking of the last line of code, I have a question about that also. The last line should have been (without my error) {member.tell()}. My question is, why couldn't this last line have been {print member}?? Every example of an iterator I've seen until this point of my learning, has had a print statement then the item variable. Instead, Swaroop uses the item variable to call the function {tell()}. This is sorta confusing to me. What if there was no function to print out the Student and Teacher variable?? How would the iterator been printed out in that case?? Thanks again, in advance. Here's the correct code. class SchoolMember: '''Represents any school member.''' def __init__(self, name, age): self.name = name self.age = age print '(Initialized SchoolMember: %s)' % self.name def tell(self): '''Tell my details.''' print 'Name:"%s" Age:"%s"' % (self.name, self.age), class Teacher(SchoolMember): '''Represents a teacher.''' def __init__(self, name, age, salary): SchoolMember.__init__(self, name, age) self.salary = salary print '(Initialized Teacher: %s)' % self.name def tell(self): SchoolMember.tell(self) print 'Salary: "%d"' % self.salary class Student(SchoolMember): '''Represents a student.''' def __init__(self, name, age, marks): SchoolMember.__init__(self, name, age) self.marks = marks print '(Initialized Student: %s)' % self.name def tell(self): SchoolMember.tell(self) print 'Marks: "%d"' % self.marks t = Teacher('Mrs. Shrividya', 40, 30000) s = Student('Swaroop', 22, 75) print # prints a blank line members = [t, s] for member in members: member.tell() # works for both Teachers and Students Output $ python inherit.py (Initialized SchoolMember: Mrs. Shrividya) (Initialized Teacher: Mrs. Shrividya) (Initialized SchoolMember: Swaroop) (Initialized Student: Swaroop) Name:"Mrs. Shrividya" Age:"40" Salary: "30000" Name:"Swaroop" Age:"22" Marks: "75" >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> You always have a choice of where to put useful code. if you put it in member functions, it can be shared by all the callers. There's no right or wrong way to do it. The only "rule" I can think of is not to mix significant calculations with prints. Make them two different methods, so the user of the class can use them independently. If you had no class member like tell(), one choice would be to enumerate the members yourself. So you could do something like: print member.name, member.age, member.marks, member.salary With some formatting. But not all members have all these fields, so you'd have to do some conditional testing, and it could get quite complex. -- DaveA

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Re: [Tutor] Tutor Digest, Vol 92, Issue 128
by Asokan Pichai Oct. 31, 2011

Oct. 31, 2011

Hugo's explanation is nice and clear. You may also want to look at this way Consider the most simplified form of the issue def alpha(): if X: beta() else: return q Here in the* if branch* nothing is returned while in the *else branch *something is being returned. That is whenever X is True nothing is returned from alpha(). Even if beta() returns something that is not being used. But when X is False something (q in this simplistic example) is being returned So this is a bug. HTH Asokan Pichai SVP - Learning and Development “Faith consists in believing when it is beyond the power of reason to believe. " Voltaire <http://www.brainyquote.com/quotes/quotes/v/voltaire163832.html>

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Re: [Tutor] Tutor Digest, Vol 92, Issue 127
by Asokan Pichai Oct. 31, 2011

Oct. 31, 2011

> From: Joel Montes de Oca <joelmontes01(a)gmail.com> > To: Tutor Python <tutor(a)python.org> > Subject: [Tutor] Paper Rock Scissors game - User's choice not returned > properly > Message-ID: <4EAEC191.3060208(a)gmail.com> > Content-Type: text/plain; charset="iso-8859-1"; Format="flowed" > > Hello everyone, > > > The function: ( http://dpaste.com/644857/) > > def UserChoice (): # The function that returns the choice from the > user > print 'Please select (P) for paper, (R) for Rock, or (S) for > Scissors.' > choice = raw_input('What is your selection?:') > > if choice.lower() not in ('p', 'r','s'): # Converts the > user's choice to lowercase and confirms the choice is valid > print 'I am sorry, you entered\'' + choice.upper() + > '\' which is an invalid response. Please try again.' > raw_input('Press Enter to try again.') > UserChoice () # If the choice is not valid, run > the function over > You should use return UserChoice() > else: > return choice > > Asokan Pichai SVP - Learning and Development “Faith consists in believing when it is beyond the power of reason to believe. " Voltaire <http://www.brainyquote.com/quotes/quotes/v/voltaire163832.html>

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importing modules and packages
by neubyr Oct. 31, 2011

Oct. 31, 2011

Is it possible to tell whether import statement is importing a module or package? I am going through some example code with some import statements - like 'import os, sys, time', 'import packed'. I know os, sys and time are (built-in) modules and 'packed' is a package here . But can I determine whether it's a package or module using any command/method or by following some naming convention? - thanks, neuby.r

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Re: [Tutor] Python Editor to Start Out WithTutor Digest, Vol 92, Issue 123
by cyclicflux＠yahoo.com Oct. 31, 2011

Oct. 31, 2011

With reference to a beginning editor, if you want to go heavy-weight go vim. Now I'm not a python expert, but I will say vim is prolly a little harder than emacs, however scripting in vim has many similarities to various types in python. The python forloop is definitely very similar to that of vim. Plus, vim may be configured for use with ipython(enhanced interactive python shell) But those are as previously mentioned very complex editors. There are others that although aren't totally as powerful will make things infinitely easier to learn. The thing that's nice about others that are ready to roll once installed, the ease in use let's you focus on learning the programming. Some of these more user friendly editors are: spyder(python editor with lots of features), or geany, which is probably the more widespread. These will with a click or few clicks provide syntax+highlighting+syntax error-checking setup. This can be difficult in the traditional text editors vim+ emacs,(I know vim) have to be compiled with certain support, as well as then have plugins installed/created, and alot of things configured. But if you wanna go w/a text editor+ python try out swaroop's site. He has two books, A Byte of Python, and A Byte of Vim. They are great for introduction stuff. But in the end learning one well makes it far easier than learning both at the same time. Good Luck!! Connected by DROID on Verizon Wireless -----Original message----- From: tutor-request(a)python.org To: tutor(a)python.org Sent: Mon, Oct 31, 2011 02:55:23 GMT+00:00 Subject: Tutor Digest, Vol 92, Issue 123 Send Tutor mailing list submissions to tutor(a)python.org To subscribe or unsubscribe via the World Wide Web, visit http://mail.python.org/mailman/listinfo/tutor or, via email, send a message with subject or body 'help' to tutor-request(a)python.org You can reach the person managing the list at tutor-owner(a)python.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Tutor digest..." Today's Topics: 1. Setting Up Emacs (Rinu Boney) 2. Re: Setting Up Emacs (Steven D'Aprano) 3. Re: Setting Up Emacs (Tim Johnson) 4. Re: Setting Up Emacs (Alan Gauld) 5. Re: Setting Up Emacs (Tim Johnson) 6. Re: Method to create small and simple database (Joel M.) 7. Re: Setting Up Emacs (Bill Allen) ---------------------------------------------------------------------- Message: 1 Date: Sun, 30 Oct 2011 18:53:04 +0530 From: Rinu Boney <rinu.matrix(a)gmail.com> To: tutor(a)python.org Subject: [Tutor] Setting Up Emacs Message-ID: <CAJTWV12yyOW+nB-+cEkZWFmP0f3wJKVYErZFoe1Kzctf7DhsRQ(a)mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" I am New To Python. I Would Like To Setup Emacs As A Python IDE. I Don't Know Anything About Emacs! Can Someone Help Me ? Thanks.

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