[Tutor] my first project: a multiplication trainer
Hello everybody, I want to create a simple multiplication trainer which quizzes me on the multiplication table. All multiplication combinations should be asked once, without repetition. Here my pseudo code: ### A = [1,2,3,4,5,6,7,8,9] B = [1,2,3,4,5,6,7,8,9] asked_questions = () false_answers = () #block 1 While tuple "asked_questions" contains less than 81 items: Take one random item from A and one random item from B If the question is NOT in "asked_questions": Add question to tuple "asked_questions" Calculate the question and wait for user-input print the question # e.g.: 3x6= If answer is false: add question to the tuple "false_answers" print: "You have answered all questions!" ### I would very much appreciate if you could comment on/criticise my pseudo code. In particular: is my approach correct, or would it be more sensible to first generate (or supply?) all possible questions and then select the ready questions randomly? So far I am not concerned about what to do with the tuple "false_answers". This I worry about later. Thanks for your help! Guba ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Working with Python Objects
"Dinesh B Vadhia" <[EMAIL PROTECTED]> wrote class A: constantA = 9 def OneOfA: a = class B: variableB = "quick brown fox" def OneOfB: b = c = b * a# the 'a' from def OneOfA in class A -- > Question: > 1) how do I access the 'a' from function (method) OneOfA in > class A so that it can be used by functions (methods) in class B? You don't and shouldn't try to. In this case because the attriute only exists inside the method, it is local, so dies when the method completes. So first of all you need to make it part of the class A. We do that by tagging it as an attribute of self, which should be the fitrst attribute of every method. But one of the concepts of OOP is to think in terms of the objects not the attributes inside them So your question should probably be: How do I access objects of class A inside methods of class B? The answer is by passing an instance into the method as a parameter. You can then manipulate the instance of A by sending messages to it. In Python you can access the instance values of an object by sending a message with the same name as the attribute - in other OOP languages you would need to provide an accessor method. But it is very important conceptually that you try to get away from thinking about accessing attributes of another object inside methods. Access the objects. Metthods should only be manipulating the attributes of their own class. To do otherwise is to break the reusability of your classes. So re writing your pseudo code: class A: constantA = 9 def OneOfA(self): # add self as first parameter self.a =# use 'self' to tag 'a' as an attribute class B: variableB = "quick brown fox" def OneOfB(self, anA):# add self and the instance of A b = c = b * anA.a# the 'a' from the instance anA This way OneOfB() only works with attributes local to it or defined as instance variables or passed in as arguments. Which is as it should be! Real OOP purists don't like direct attribute access but in Python its an accepted idiom and frankly there is little value in writing an accessor method that simply returns the value if you can access it directly. The thing you really should try to avoid though is modifying the attributes directly from another class. Normally you can write a more meaningful method that will do that for you. -- Alan Gauld Author of the Learn to Program web site Temorarily at: http://uk.geocities.com/[EMAIL PROTECTED]/ Normally: http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] My tutor is back
I have no idea why it took my ISP so long but after 4 weeks my Tutorial is finally back up on its original address... Hooray! Alan G. http://www.freenetpages.co.uk/hp/alan.gauld/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Working with Python Objects
Dinesh wrote: > I've avoided it as long as possible but I've reached a stage where I have to > start using Python objects! The primary reason is that the web framework uses > objects and the second is to eliminate a few globals. Here is example pseudo > code followed by the question (one of many I suspect!): > > class A: > constantA = 9 > def OneOfA: > > a = > > class B: > variableB = "quick brown fox" > def OneOfB: > > b = > c = b * a# the 'a' from def OneOfA in class A > > Question: > 1) how do I access the 'a' from function (method) OneOfA in class A so that > it can be used by functions (methods) in class B? I wrote the following classes as an example that might be what you want. 1 class A(object): 2 def one_of_a(self): # self is required for a method 3 self.a = 3 4 print self.a 5 6 class B(object): 7 def one_of_b(self, a_obj): 8 b = 10 9 self.c = b * a_obj.a 10 print self.c First of all, note that the method definitions have a "self" argument. This is how the method has access to the object for which they are called. If you look on line 3, I put "self.a" so that the 3 is stored in the "a" field of the object. Since you wanted to access the a field of an A object in your one_of_b method, it will need access to an A object, so I added a parameter that you can use to pass in an A object (line 7). Assuming an A object is passed in, then the a field of it can be accessed as in line 9, "a_obj.a". Here is how I ran the code (using IPython): In [17]: v1 = A() In [18]: v1.one_of_a() 3 In [19]: v2 = B() In [20]: v2.one_of_b(v1) 30 At [17], I create an instance of A and assign it to variable v1. At [18] I call the one_of_a method on my newly created object, which prints out a 3, the value stored in the "a" field of v1 object. At [19], I create an instance of B and assign it to variable v2. At [20], I call the one_of_b method on my new object, passing in the A object assigned to v1. It prints out 30, which is 10 times the value in the "a" field of v1. The class, variable, and method names are pretty abstract and similar, so I hope that doesn't cause undue confusion. It might be easier to understand with a more concrete example. Greg ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] hypotenuse
Robert Childers wrote:
> I have rewritten my "hypotenuse" program as follows:>>> #This program
> calculates the width and diagonal of a golden rectangle
> >>> print "Calculate the width and diagonal of a golden rectangle."
> Calculate the width and diagonal of a golden rectangle.
> >>> height = input ("Input height:")
> Input height:1
> >>> width = height*1.618
> >>> print "Width:", width
> Width: 1.618
> >>> import math
> >>> hyp_squared = height**2 + width**2
> >>> hypotenuse = math.sqrt(hyp_squared)
> >>> print "Diagonal:", hypotenuse
> Diagonal: 1.90208412012
>
> When I save the program then try to run the module I get an error
> message that it is invalid.
Please ALWAYS post the code and the traceback. Otherwise we have no way
to easily help you.
But I will take a guess that you saved the contents of the interactive
session and tried to run that. That will not work, as the interactive
session is full of >>> and results of print statements.
So I suggest you edit the module to see if this is the case; if it is
then remove all the junk so you just have pure Python. Run that. If you
still get errors post the code and traceback.
--
Bob Gailer
919-636-4239 Chapel Hill, NC
___
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
[Tutor] pydoc introspecting info via OptionParser?
I'm trying to do nice clean documentation for a python script I run from the command-line, and I'd like pydoc or a similar program to document it well. But I don't want to duplicate option information by putting it both in my docstring and in optparse. I would think that pydoc might notice an OptionParser instance at the module level and show the options defined there, but it doesn't seem to. Would it be hard to add to pydoc? Do any other documentation programs do that? I know that on aspn there is a library to parse a docstring and pass options to optparse: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/278844 But it has limitations (doesn't support all of optparse, won't work with -OO) and is a bit uglier. Cheers, Neal McBurnett http://mcburnett.org/neal/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Working with Python Objects
I've avoided it as long as possible but I've reached a stage where I have to start using Python objects! The primary reason is that the web framework uses objects and the second is to eliminate a few globals. Here is example pseudo code followed by the question (one of many I suspect!): class A: constantA = 9 def OneOfA: a = class B: variableB = "quick brown fox" def OneOfB: b = c = b * a# the 'a' from def OneOfA in class A Question: 1) how do I access the 'a' from function (method) OneOfA in class A so that it can be used by functions (methods) in class B? Cheers Dinesh ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] hypotenuse
I have rewritten my "hypotenuse" program as follows:>>> #This program
calculates the width and diagonal of a golden rectangle
>>> print "Calculate the width and diagonal of a golden rectangle."
Calculate the width and diagonal of a golden rectangle.
>>> height = input ("Input height:")
Input height:1
>>> width = height*1.618
>>> print "Width:", width
Width: 1.618
>>> import math
>>> hyp_squared = height**2 + width**2
>>> hypotenuse = math.sqrt(hyp_squared)
>>> print "Diagonal:", hypotenuse
Diagonal: 1.90208412012
When I save the program then try to run the module I get an error message
that it is invalid.
I have been assuming that if no "invalid syntax" error occurs in the shell
the program should run. Could this problem be associated with the import
math instruction?
On Fri, Mar 14, 2008 at 6:03 AM, Alan Gauld <[EMAIL PROTECTED]>
wrote:
> "Wolfram Kraus" <[EMAIL PROTECTED]> wrote in message
> news:[EMAIL PROTECTED]
> > Am 14.03.2008 09:40, Alan Gauld schrieb:
> Why can you not use something like:
>
> >>> hypotenuse = hyp_squared**1/2
> >>
> >> And for completeness that could also be written:
> >>
> >> hypotenuse = pow(hyp_squared,1/2)
> >>
> >> Again, without the need to import math.
> >>
> > But beware of the integer divison in Python:
> >
> > >>> pow(2,1/2)
> > 1
>
> Good catch. Applies to the ** style too.
>
> Alan G
>
>
> ___
> Tutor maillist - Tutor@python.org
> http://mail.python.org/mailman/listinfo/tutor
>
___
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] hypotenuse
"Wolfram Kraus" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Am 14.03.2008 09:40, Alan Gauld schrieb: Why can you not use something like: >>> hypotenuse = hyp_squared**1/2 >> >> And for completeness that could also be written: >> >> hypotenuse = pow(hyp_squared,1/2) >> >> Again, without the need to import math. >> > But beware of the integer divison in Python: > > >>> pow(2,1/2) > 1 Good catch. Applies to the ** style too. Alan G ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Idle
"Michael Connors" <[EMAIL PROTECTED]> wrote > You need to put : > import random > > or alternatively use: > from random import * Or better still use from random import randrange import * style is not recommended because of the dangers of polluting the namespace -- Alan Gauld Author of the Learn to Program web site Temorarily at: http://uk.geocities.com/[EMAIL PROTECTED] Normally: http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Idle
I'm very new to Python, but it seems like I just learned in a class for
a random number, you would need the :
import random
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Christopher Marlett
Sent: Thursday, March 13, 2008 7:44 PM
To: tutor@python.org
Subject: [Tutor] Idle
Hi, I'm trying to write a program that uses the range function to
produce and then print [1, 2, 3, 4]. then prompt the user for an integer
n and print the list [1, 2, 3, ... , n] - including n. Then use a simple
repeat loop to print five randomly chosen numbers from the range [1, 2,
3, ... , n]
This is what I have done so far
print [1,2,3,4]
nstring = raw_input("Enter any number: ")
n = int(nstring)
print range(1,n+1)
y = random.randrange(1,n)
print y
It all works up until I need to print five randomly chosen numbers from
the range [1,n]. It tells me that random is not defined.
Thank you for your time.
___
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
___
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Idle
> > It all works up until I need to print five randomly chosen numbers from > the range [1,n]. It tells me that random is not defined. You need to put : import random in your program before doing: y = random.randrange(1,n) or alternatively use: from random import * and call the function as follows: y = randrange(1,n) Regards, -- Michael Connors ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Idle
Hi, I'm trying to write a program that uses the range function to
produce and then print [1, 2, 3, 4]. then prompt the user for an integer
n and print the list [1, 2, 3, ... , n] – including n. Then use a simple
repeat loop to print five randomly chosen numbers from the range [1, 2,
3, ... , n]
This is what I have done so far
print [1,2,3,4]
nstring = raw_input("Enter any number: ")
n = int(nstring)
print range(1,n+1)
y = random.randrange(1,n)
print y
It all works up until I need to print five randomly chosen numbers from
the range [1,n]. It tells me that random is not defined.
Thank you for your time.
___
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] hypotenuse
Am 14.03.2008 09:40, Alan Gauld schrieb: >>> Why can you not use something like: >>> >> hypotenuse = hyp_squared**1/2 > > And for completeness that could also be written: > > hypotenuse = pow(hyp_squared,1/2) > > Again, without the need to import math. > But beware of the integer divison in Python: >>> pow(2,1/2) 1 >>> pow(2,.5) 1.4142135623730951 >>> pow(2,1.0/2) 1.4142135623730951 ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] hypotenuse
>> Why can you not use something like: >> >> >>>hypotenuse = hyp_squared**1/2 And for completeness that could also be written: hypotenuse = pow(hyp_squared,1/2) Again, without the need to import math. -- Alan Gauld Author of the Learn to Program web site Temorarily at: http://uk.geocities.com/[EMAIL PROTECTED]/ Normally: http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
