Re: [Tutor] Workaround for limitation in xrange()?
--- Dick Moores [EMAIL PROTECTED] wrote: Andrei's Write your own iterator: def hugerange(minval, maxval): ... val = minval ... while val maxval: ... yield val ... val += 1 All 3 are essentially the same, aren't they. Which makes me feel even dumber, because I don't understand any of them. I've consulted 3 books, and still don't understand the use of yield. This is an example of a coroutine. See http://en.wikipedia.org/wiki/Coroutine def hugerange(minval, maxval): val = minval while val maxval: yield val ### return value of val to calling routine ### at this point and place ### hugerange() function temporarily ### on hold ... ### ### next call to hugerange() ### resumes at this point with ### all previous variable values ### still intact ... val += 1 __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Help
--- Kefka Palazzo [EMAIL PROTECTED] wrote: I am trying to learn a programming language good for programming entire games (core functions too) similar to both the Final Fantasy and Metroid series. From the book I'm learning from (Python Programming for the Absolute Beginner, by Michael Dawsom) it seems like within a week or two I'll have a basic grasp on most of the functions, but I want to know if it will be worth it for what I need it for or if I would be better off learning something different (and harder .) From the http://panda3d.org website: Panda3D is a 3D engine: a library of subroutines for 3D rendering and game development. The library is C++ with a set of Python bindings. Game development with Panda3D usually consists of writing a Python program that controls the the Panda3D library. Panda3D was developed by Disney for their massively multiplayer online game, Toontown. It was released as free software in 2002. Panda3D is now developed jointly by Disney and Carnegie Mellon University's Entertainment Technology Center __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looking for an edutainment-type introduction to programming book
Look here: www.ceebot.com Not a book, but it might be what you are looking for. --- Abel Daniel [EMAIL PROTECTED] wrote: Hi! I'm looking for a book to give to my younger brother as a birthday present. He is 13 years old, had some experience with logo (but not much, so he knows about simple instructions and loops, but not about, say, algorithms), and is fairly comfortable around computers. He sometimes mentions that he would like to learn programming, but so far my only attempt to teach him was an absolute failure, due mostly to my total lack of pedagogical skills. (I tried to start with the concept of abstract objects, with predictable effects...) What I am looking for is a book thats: 1) simple, and fun enough so that he can learn from it without my continous assistence. (Of course, I can answer questions, but the idea is that I don't want to walk him through all of it.) 2) doesn't look like it is teaching programming -- it should be more like playing with the computer, and having fun style, with the learning programming being a sort of side-effect. Ideally it would use python, but thats not that strict a requirement, squeak or logo might be acceptable, as well. (Although I'm prejudiced towards python, that being my favourite programming language.) Similarly, being a book isn't a requirement either, so a pdf, or an online tutorial would be fine as well, although a book would be better. I tried to search for such books, but I mostly found 'now we are going to learn programming' types, and I would like something more subtle, and more motivating than that. Any suggestions? -- Abel Daniel ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] about assert
--- linda.s [EMAIL PROTECTED] wrote: Python manual has a very brief introduction of assert statements. It is very difficult for me to understand it. Every program has some fundamental assumptions that must remain true in order for the program to continue giving correct results. The assert statement is used to verify those assumptions. (The optional 2nd parameter can be used to give additional information about what went wrong.) For example, in my world no one is allowed to have a negative age. A negative age means my program is hopelessly confused and should halt immediately. myAge=42 assert myAge=0 ## this is OK myAge= -1## logically impossible assert myAge = 0 Traceback (most recent call last): File interactive input, line 1, in ? AssertionError ## here I print the condition that failed assert myAge =0, 'myAge = 0' Traceback (most recent call last): File interactive input, line 1, in ? AssertionError: myAge = 0 __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] When am I ever going to use this?
--- Christopher Spears [EMAIL PROTECTED] wrote: I've been working through a tutorial: http://www.ibiblio.org/obp/thinkCSpy/index.htm. Lately, I have been learning about abstract data types (linked lists, stacks, queues, trees, etc.). While I do enjoy the challenge of creating these objects, I am not sure what they are used for. You probably use a linked list every day and don't even know it. Do you ever hit the Back button on your web browser to return to previous pages? The browser keeps a list of the pages you've visited, all linked together, so you can move backwards and forwards through the list. Here is a great resource for learning about different kinds of data structures: http://www.nist.gov/dads Regards, Marc __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] no loops
--- John Fouhy [EMAIL PROTECTED] wrote: On 12/07/06, Christopher Spears [EMAIL PROTECTED] wrote: Now the exercise is: As an exercise, rewrite this function so that it doesn't contain any loops. I have been staring at this function and drawing a blank. Something tells me that I need to use iteration, but I am not sure how I could implement it. Hi Chris, You are using iteration. That's what loops are :-) Perhaps you meant to say recursion, which is where a function calls itself. You could solve this recursively, but I think Gregor's comment is closer to what they want you to do. -- John. I agree with Gregor and John. What makes the problem difficult is the fact that time is represented using 3 different units of measure: hours, minutes, and seconds. The math becomes much simpler if you convert the time value to a single unit (such as seconds). But it doesn't have to be seconds. I recall seeing one database that stores time as fractional hours where a minute is worth 1/60 of an hour and a second is worth 1/3600 of an hour. In other words, 1:15 is stored as 1.25 hours, 4:30 is stored as 4.5 hours, and so forth. Converting from (hours, minutes, seconds) to fractional hours is pretty easy, but going the other way is not so simple. __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need Help
--- Terry Carroll [EMAIL PROTECTED] wrote: On Tue, 11 Jul 2006, Michael P. Reilly wrote: Another aspect of your assignment will be to be able to use this functionality from the command-line. This means: without asking questions from the user, but input is being passed as arguments. John should get clarification from his instructor, but I did not read it that way. I read that requirement to support a command line query as meaning the program should prompt the user to enter a query command; as opposed to hard-coding the transactions in the coe itself (as is sometimes done at an intro level). ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor This may be the most important lesson to learn from this exercise: even experienced programmers can (and do) interpret requirements differently. When in doubt, ask! __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Logical Sorting
I did a Google search for python numeric sort and found http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/135435 It seems to do what you want. Marc --- Evan Klitzke [EMAIL PROTECTED] wrote: Hi, I am trying to sort a list of directories that correspond to kernel sources under /usr/src/linux. I wrote some code that gets a list like this: ['linux-2.6.9-gentoo-r4', 'linux-2.6.16-gentoo-r11/', 'linux-2.6.16-gentoo-r7/'] When I sort the list, I want it to go from oldest (lowest version) to newest, so the sorted list should look like this: ['linux-2.6.9-gentoo-r4', 'linux-2.6.16-gentoo-r7/', 'linux-2.6.16-gentoo-r11/'] The problem is that since the built in string comparisons compare character by character, so the sort puts 2.6.16 before 2.6.9, and -r11 before -r7. This is obviously not what I want. My question is: are there any modules or built in methods that will do a logical sort on a list like this, and sort it the way I want, or will I have to write my own sorting function? -- Evan Klitzke P.S. I know that the simplest way is just to use ls to sort by time, but it is not necessarily true that older kernel versions have an older time stamp :-) ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] counting number of inputs (EARLIER VERSION SENT ACCIDENTLY)
Michelle:
Are you familiar with writing functions?
Here I've created a function named getInputs.
I've also created a few test cases to verify that (a)
my understanding of the problem is correct, and (b) my
solution is correct.
It's important to think about how your program is
supposed to behave in different situations. Do you
think these 3 tests are enough to prove that the code
is correct?
#
## start of code ##
#
def getInputs():
Description:
Collect numbers entered by the user (up to a
maximum of 5 values) and
store them in the listOfValues.
Stop collecting numbers if the user enters -1
or if 5 numbers have been collected.
If the user entered -1, the -1 is NOT returned
as part of the list.
listOfValues = [] ## this list holds the values
entered by the user
for i in range(5):
newValue = int(raw_input('Enter a number [-1
to exit]:'))
if newValue == -1:
# Return right now with whatever is
currently in the list.
return listOfValues
else:
# Add this new value to the list and keep
looping.
listOfValues.append(newValue)
## If we got this far, it means the user did not
enter a -1 so
## the list contains 5 values.
return listOfValues
Here are a few test cases to verify the logic of my
code.
Test Case 1:
INPUTS:
first entered value: -1
RESULT:
function returns empty list
Test Case 2:
INPUTS:
first entered value: 1
second entered value: 2
third entered value: -1
RESULT:
returned list contains [1,2]
Test Case 3:
INPUTS:
first entered value: 1
second entered value: 2
third entered value: 3
fourth entered value: 4
fifth entered value: 5
RESULT:
returned list contains [1,2,3,4,5]
if __name__ == __main__:
print getInputs()
###
## end of code ##
###
--- Python [EMAIL PROTECTED] wrote:
On Wed, 2006-05-03 at 15:33 -0400, MICHELLE EVANS
wrote:
OK, I've tried a different approach to this.
How do I get this to stop by using -1?
I do not want this to print until either 5 inputs
have been entered or -1
has been entered. See below:
use a for block rather than a while block to
have a normal limit of
5 repetitions:
for x in range(5):
will repeat 5 times with x running from 0 to 4.
x is ignored - unless some use for it does turn up.
the break statement allows you to terminate a block,
so
if number == -1: break
will end the for block.
Now, one of the cute features in Python is the else
clause that goes
with the for and while blocks. The else block is
executed when there is
no break. So the skeleton for your program can look
something like
for x in range(5):
# get inputs and break on -1
else:
# no break so just process the inputs
Good luck.
# Add number of per hour
numbers = []
stop = None
while stop != -1:
number = int(raw_input(Run number(-1 to end)
: ))
numbers.append(number)
print
for number in numbers:
print number
- Original Message -
From: Python [EMAIL PROTECTED]
To: MICHELLE EVANS [EMAIL PROTECTED]
Cc: Tutor Python tutor@python.org
Sent: Wednesday, May 03, 2006 12:18 PM
Subject: Re: [Tutor] counting number of inputs
(EARLIER VERSION SENT
ACCIDENTLY)
(Tip: Best to use reply-to-all when responding
to an email on the list)
On Tue, 2006-05-02 at 21:34 -0400, MICHELLE
EVANS wrote:
number1 = int(raw_input(Run number 1 (-1 to
end) : ))
number2 = int(raw_input(Run number 2 (-1 to
end) : ))
number3 = int(raw_input(Run number 3 (-1 to
end) : ))
number4 = int(raw_input(Run number 4 (-1 to
end) : ))
number5 = int(raw_input(Run number 5 (-1 to
end) : ))
Good. You collect the string from raw_input and
convert it to an
integer.
This will prompt for 5 inputs, but it is missing
any logic to actually
break if -1 is entered. With a language like
BASIC, you could stick in
tests sort of like:
if number1 == -1 goto done:
BUT Python does not have a goto. So we actually
need some flow
control around the block of code where you
collect inputs.
while blocks process an indefinite number of
times while a test
condition is True.
for blocks iterate through a sequence until they
reach the end. By
providing a sequence with the correct count, you
can repeat the block
the correct number of times. The range (and
xrange for big sequences)
functions provide a sequence of integers that
can be used conveniently
with for.
The easiest way to fix your code above would be
something like:
ask_for_number = True
while ask_for_number:
number1 =
if number1 == -1: break
...
number5 = ...
ask_for_number = False
HOWEVER,
