Re: [Tutor] help with random.randint
On Wednesday February 3 2010 12:26:43 David wrote: > thanks for the explanation, all this is really helpful -- I certainly > have learned sth. today! > I wonder, though, how I would get my number pairs, which I need later > on, if I were to follow your solution. I am asking because as I > understand your code, the list terms is a list of integers here, but not > of x,y pairs, right? (I can see that this was a problem of my code right > from the start, btw.) Maybe I don't understand you correctly; but if you know that you only need two random numbers I would create the list like this: import random xy = [random.randint(1, 99), random.randint(1, 99)] Or maybe a use tuple and a little code beautification: import random randint = random.randint xy = (randint(1, 99), randint(1, 99)) Off course you can put these small lists or tuples into another list: import random randint = random.randint num_terms = 5 terms = [] for i in range(num_terms): terms += [(randint(1, 99), randint(1, 99))] print terms Eike. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint
On Wed, Feb 3, 2010 at 5:26 AM, David wrote: > Hello Eike, > > thanks for the explanation, all this is really helpful -- I certainly have > learned sth. today! > I wonder, though, how I would get my number pairs, which I need later on, > if I were to follow your solution. I am asking because as I understand your > code, the list terms is a list of integers here, but not of x,y pairs, > right? (I can see that this was a problem of my code right from the start, > btw.) > > David I'll refer you to what I posted in (what appeared to me as) your other thread: If you want the unique pairs (i.e. (12,7) is equivalent to (7,12)), I *think* you can do a simple chain: pool = [] for x in xrange(1,13): for y in xrange(x, 13): pool.append((x,y)) because that will give you the sets ordered by the smallest - you'll get 1x1-12, then 2x2-12, etc. HTH, Wayne ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint (cont. -- now: pseudo code)
On Wed, Feb 3, 2010 at 12:12 AM, David wrote: > def createQuestions: >generate all multiplication combinations possible >append as tuple to pool >eliminate 'mirrored doubles' (i.e. 7x12 and 12x7) >randomize pool > > I haven't really looked through most of this stuff - but your mirrored doubles has a somewhat cleaner solution than generating all then removing the duplicates, I think. Referring to here: http://docs.python.org/reference/expressions.html#notin I *think* you can create a list of all the non-mirrored pairs this way: pool = [] for x in xrange(1,13): for y in xrange(x, 13): pool.append((x,y)) Then I would shuffle the pairs and the pairs within: i.e.: for x in xrange(len(pool)): # We want the index, not just the element if random.randint(0,1): pool[x] = pool[x][::-1]# A simple reversal swaps the values else: pass now you have two options - either shuffle your pool, or pick random elements and pop them out of your list: (this worked at least once on a 10 element list): while pool: pool.pop(random.randint(0, len(pool)-1))) of course you'd probably assign that tuple to some useful value or function call. But that's what I'd do... and given the fact that I was actually planning to make a "game" somewhat like this myself, this gives me a good excuse to write some of the code ^_^ HTH, and thanks for asking a question that motivates, Wayne ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint
Hello Eike, thanks for the explanation, all this is really helpful -- I certainly have learned sth. today! I wonder, though, how I would get my number pairs, which I need later on, if I were to follow your solution. I am asking because as I understand your code, the list terms is a list of integers here, but not of x,y pairs, right? (I can see that this was a problem of my code right from the start, btw.) David On 03/02/10 19:08, Eike Welk wrote: Hello David! On Wednesday February 3 2010 04:21:56 David wrote: import random terms = [] for i in range(2): terms = random.randint(1, 99) print terms Here is an other solution, which is quite easy to understand and short: import random terms = [] for i in range(2): terms += [random.randint(1, 99)] print terms Note the rectangular brackets around "[random.randint(1, 99)]". This creates a list which a single number in it. This small list can then be added to the already existing list "terms". Eike. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint
Hello David! On Wednesday February 3 2010 04:21:56 David wrote: > > import random > terms = [] > for i in range(2): > terms = random.randint(1, 99) > print terms Here is an other solution, which is quite easy to understand and short: import random terms = [] for i in range(2): terms += [random.randint(1, 99)] print terms Note the rectangular brackets around "[random.randint(1, 99)]". This creates a list which a single number in it. This small list can then be added to the already existing list "terms". Eike. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint (cont. -- now: pseudo code)
On Wed, 03 Feb 2010 14:12:42 +0800
David wrote:
> Hello Benno, list,
>
> thanks for those clarifications, which, well, clarify things ;-)
>
> This is my latest creation:
>
> import random
>
> def createTerms():
> terms = []
> for i in range(2):
> terms.append(random.randint(1, 99))
> j = terms[0]
> k = terms[1]
> print "%3d\nx%2d" % (j, k)
>
> createTerms()
I find
j,k = terms
clearer. (This will automagically unpack items from terms.)
> Which works. However, it merely prints a multiplication task. Anyway,
> this was just a prelude. In the end, I want far more, namely to create,
> ask, and verify some multiplication questions. Here is my pseudo code of
> this little project:
>
>
>
> pool = []
> correct = 0
> incorrect = 0
>
> def createQuestions:
> generate all multiplication combinations possible
> append as tuple to pool
> eliminate 'mirrored doubles' (i.e. 7x12 and 12x7)
Unneeded. Instead building all combinations looping with j=1..n & k=1..n,
directly avoid duplicates using j=1..n & k=j..n. (not 100% sure, though)
> randomize pool
>
> def askQuestions:
> for question in pool:
> calculate solution
> take answer from user
> if user answer == solution:
> correct += 1
> remove question from pool
> else:
> incorrect += 1
>
> def showStats:
> print number of questions asked
> print number of questions answered correctly
> print percentage of correct answers
>
> def askFaultyAnswers:
> answer = raw_input("Try again the incorrect questions? (y/n) ")
> if answer == "y":
> aksQuestions()
> else:
> break
>
>
> createQuestions()
> askQuestions()
> showStats()
> askFaultyAnswers()
> print "good-bye!"
>
>
>
> I think it is sensible to
>
> * first create all possible solutions, then
> * kick out doublettes, and only then
> * ask questions
>
> I have some questions though:
>
> Is the overall structure and flow of this program okay? What are the
> main problems you can spot immediately?
>
> In the very end I would like to take this code as a basis for a wxPython
> program. Are there any structural requirements I am violating here?
You should from start on organize your code into funcs that will be so-called
"callback functions", meaning functions that will be called by user actions
(typically button press). Hope it's clear. This does not prevent an OO
structure of the code, indeed, the funcs can well be object methods if this
matches the problem.
> If I want to limit the number of questions asked, say to 20, would I
> operate with slicing methods on the randomised pool?
?
> How would you go about showing stats for the second run (i.e. the
> FaultyAnswers)? Right now I am thinking of setting the global variables
> correct and incorrect to 0 from _within_ askFaultyAnswers; then I would
> run showStats() also from _within_ askFaultyAnswers. Good idea?
I would have a kind of overall "UserTest" object with methods generating and
storing test data (numbers), asking questions and getting answers, recording
and outputing results.
This is an OO point of view. You may organise things differently (but even then
an OO pov sometimes helps structuring a pb).
Denis
la vita e estrany
http://spir.wikidot.com/
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Re: [Tutor] help with random.randint
On Wed, 03 Feb 2010 11:21:56 +0800 David wrote: > Hello list, > > I thought this was easy even for me, but I was wrong, I guess. > Here is what I want to do: take two random numbers between 1 and 99, and > put them into a list. > > import random > terms = [] > for i in range(2): > terms = random.randint(1, 99) > print terms > > This prints just one number (the last one generated in the loop?) Yo, terms now refers to a simple integer. What you want is instead: for i in range(2): term = random.randint(1, 99) terms.append(term) # put new item at end of list print terms > So I tried to change line 4 to the following: > terms += random.randint(1, 99) This is equivalent to terms = terms + random.randint(1, 99) Because the first operand is a list, python won't do an addition (yes, the operator can be misleading, I would personly prefer eg '++' to avoid ambiguity), but a so-called "concatenation" (yes, that word is ugly ;-). This "glues" together 2 sequences (lists or strings). In this case, you get an error because the second operand is not a sequence. Denis la vita e estrany http://spir.wikidot.com/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint (cont. -- now: pseudo code)
On Wed, Feb 3, 2010 at 10:06 AM, David wrote: > Bob, > > brilliant stuff -- I am truly awed by this. Create a default-filled matrix > and mark combinations used so as to take them out of the game? Wow. This is > new to me. > > On 03/02/10 15:46, bob gailer wrote > >> def askQuestions(): # generate and ask questions: >> for i in range(NQ): >> while 1: # loop till we get an unused combo >> x, y = [random.randint(1,MAX) for i in 'ab'] >> if mtable[x][y] == 1: # combo is available >> break >> askQuestion(x,y) >> # indicate asked >> mtable[x][y] = 0 >> mtable[y][x] = 0 > > Here you lose me, though. Where does mtable come from, what does it do? You > don't introduce it as a variable, and when I google it, nothing much comes > of if... > I think mtable should be replaced by the pool variable defined at the top. Then it makes sense. Second, I think a two-dimensional approach is rather wasteful here, it's clearer and simpler to keep a list of generated questions (you already do that anyway), and for each new question answered, do: if (x, y) in generated: continue else: generated.append((x, y)) The random generating approach is more efficient if you're only going to use a small subset of the possible set of questions. If you're going to use almost the entire set, though, calculating them is more efficient, since the random generator will come across more and more duplicates as it fills up the array. Here's an alternative approach that uses itertools.combinations to calculate all possible sequences and then shuffles: import itertools import random # maximum number and number of questions MAX = 20 NQ = 10 def gen_questions(): # start at 2, since 0 * x and 1 * x aren't very interesting q = list(itertools.combinations(range(2, MAX), 2)) random.shuffle(q) return q Note that, if MAX is high, it will take a very long time to generate all possible questions. (1000 was a second or so on my computer, but 10.000 took longer than I was willing to wait). If you're not going to use all of those questions, (and it's likely you won't, since a range of ten numbers already provides 45 different questions), then the random generation is better. Hugo ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint
On Wed, Feb 3, 2010 at 8:19 AM, David wrote: > Hello Bob, > > thanks for your comments! > > > On 03/02/10 14:51, bob gailer wrote: > >> or if you seek terseness: >> >> terms = [random.randint(1, 99) for i in 'ab'] > > Do I understand correctly that 'ab' here merely serves to produce a 'dummy > sequence' over which I can run the for loop? > That is correct. you could have used any two-character sequence. I think the range(2) call is clearer and more pythonic though. And it's not that much longer Hugo ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint (cont. -- now: pseudo code)
Bob, brilliant stuff -- I am truly awed by this. Create a default-filled matrix and mark combinations used so as to take them out of the game? Wow. This is new to me. On 03/02/10 15:46, bob gailer wrote def askQuestions(): # generate and ask questions: for i in range(NQ): while 1: # loop till we get an unused combo x, y = [random.randint(1,MAX) for i in 'ab'] if mtable[x][y] == 1: # combo is available break askQuestion(x,y) # indicate asked mtable[x][y] = 0 mtable[y][x] = 0 Here you lose me, though. Where does mtable come from, what does it do? You don't introduce it as a variable, and when I google it, nothing much comes of if... David ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint (cont. -- now: pseudo code)
David wrote:
[snip]
My suggestion (untested):
MAX = 12
NQ = 20 # of questions to ask
# create a 2 dimensional array of 1's
row = [1]*MAX
pool = [row[:] for i in range(MAX)]
incorrect = [] # store incorrectly answered combos here
def askQuestions(): # generate and ask questions:
for i in range(NQ):
while 1: # loop till we get an unused combo
x, y = [random.randint(1,MAX) for i in 'ab']
if mtable[x][y] == 1: # combo is available
break
askQuestion(x,y)
# indicate asked
mtable[x][y] = 0
mtable[y][x] = 0
showStats()
def askQuestion(x,y):
solution = x*y
# take answer from user
ok = user answer == solution
if ok:
correct += 1
else:
incorrect.append((x,y))
return ok
def askFaultyAnswers():
answer = raw_input("Try again the incorrect questions? (y/n) ")
if answer == "y":
correct = 0
for x,y in incorrect:
ok = askQuestion(x,y)
# could use ok to remove combo from incorrect list.
showStats()
askQuestions()
askFaultyAnswers()
print "good-bye!"
I think it is sensible to
* first create all possible solutions, then
* kick out doublettes, and only then
* ask questions
I have some questions though:
Is the overall structure and flow of this program okay? What are the
main problems you can spot immediately
Calculating kicking randomizing is overkill. My code uses a 2 dimension
array to track which x,y combos are available.
break is only valid within a loop.
Recursively calling askQuestions is not a good idea. Save recursion for
when it is is meaningful. Use a loop instead.
There is no need for an incorrect counter. we can calculate it later
(incorrect = NQ -correct)
In the very end I would like to take this code as a basis for a
wxPython program. Are there any structural requirements I am violating
here?
Not that I can see. It is common practice to separate logic from display.
If I want to limit the number of questions asked, say to 20, would I
operate with slicing methods on the randomised pool?
My solution does not use a randomized pool. Just a loop over range(NQ)
How would you go about showing stats for the second run (i.e. the
FaultyAnswers)? Right now I am thinking of setting the global
variables correct and incorrect to 0 from _within_ askFaultyAnswers;
then I would run showStats() also from _within_ askFaultyAnswers. Good
idea?
Yes indeed. That is what I did before reading your comment! Great minds
think alike.
--
Bob Gailer
919-636-4239
Chapel Hill NC
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Re: [Tutor] help with random.randint
Hello Bob, thanks for your comments! On 03/02/10 14:51, bob gailer wrote: or if you seek terseness: terms = [random.randint(1, 99) for i in 'ab'] Do I understand correctly that 'ab' here merely serves to produce a 'dummy sequence' over which I can run the for loop? David ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint
David wrote: Hello list, I thought this was easy even for me, but I was wrong, I guess. Here is what I want to do: take two random numbers between 1 and 99, and put them into a list. [snip] Or you can use list comprehension: terms = [random.randint(1, 99) for i in range(2)] or if you seek terseness: terms = [random.randint(1, 99) for i in 'ab'] -- Bob Gailer 919-636-4239 Chapel Hill NC ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] help with random.randint (cont. -- now: pseudo code)
Hello Benno, list,
thanks for those clarifications, which, well, clarify things ;-)
This is my latest creation:
import random
def createTerms():
terms = []
for i in range(2):
terms.append(random.randint(1, 99))
j = terms[0]
k = terms[1]
print "%3d\nx%2d" % (j, k)
createTerms()
Which works. However, it merely prints a multiplication task. Anyway,
this was just a prelude. In the end, I want far more, namely to create,
ask, and verify some multiplication questions. Here is my pseudo code of
this little project:
pool = []
correct = 0
incorrect = 0
def createQuestions:
generate all multiplication combinations possible
append as tuple to pool
eliminate 'mirrored doubles' (i.e. 7x12 and 12x7)
randomize pool
def askQuestions:
for question in pool:
calculate solution
take answer from user
if user answer == solution:
correct += 1
remove question from pool
else:
incorrect += 1
def showStats:
print number of questions asked
print number of questions answered correctly
print percentage of correct answers
def askFaultyAnswers:
answer = raw_input("Try again the incorrect questions? (y/n) ")
if answer == "y":
aksQuestions()
else:
break
createQuestions()
askQuestions()
showStats()
askFaultyAnswers()
print "good-bye!"
I think it is sensible to
* first create all possible solutions, then
* kick out doublettes, and only then
* ask questions
I have some questions though:
Is the overall structure and flow of this program okay? What are the
main problems you can spot immediately?
In the very end I would like to take this code as a basis for a wxPython
program. Are there any structural requirements I am violating here?
If I want to limit the number of questions asked, say to 20, would I
operate with slicing methods on the randomised pool?
How would you go about showing stats for the second run (i.e. the
FaultyAnswers)? Right now I am thinking of setting the global variables
correct and incorrect to 0 from _within_ askFaultyAnswers; then I would
run showStats() also from _within_ askFaultyAnswers. Good idea?
Many thanks for your guidance and input!
David
On 03/02/10 12:25, Benno Lang wrote:
On Wed, Feb 3, 2010 at 12:21 PM, David wrote:
Hello list,
I thought this was easy even for me, but I was wrong, I guess.
Here is what I want to do: take two random numbers between 1 and 99, and put
them into a list.
import random
terms = []
for i in range(2):
terms = random.randint(1, 99)
All you're doing here is assigning an integer value to 'terms', twice.
This assignment means 'terms' is no longer a list, but is now just an
int. What you want is probably:
terms.append (random.randint(1, 99))
So I tried to change line 4 to the following:
terms += random.randint(1, 99)
You can't freely mix types with python operators, i.e. a_list += an_int
But you can use += with 2 ints or 2 lists, so you could do:
terms += [random.randint(1, 99)]
I think using append is much nicer though.
I understand this error thus: once an int has been placed into the list
terms, no further int can be added. But: terms is a mutable list, and NOT an
'int' object!
The int was never added to the list in the first place, because list
+= int is not something Python understands.
So here are my questions: what is the problem, and how can I generate two
random numbers and store them (preferably in a tuple)?
I hope what I wrote above answers the first question.
IIRC tuples are immutable, so you either to create the list first and
then convert it to a tuple:
terms_tuple = tuple(terms)
Or you can create a tuple from the beginning (without a loop):
terms_tuple = (random.randint(1, 99), random.randint(1, 99))
HTH,
benno
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Re: [Tutor] help with random.randint
On Wed, Feb 3, 2010 at 12:21 PM, David wrote: > Hello list, > > I thought this was easy even for me, but I was wrong, I guess. > Here is what I want to do: take two random numbers between 1 and 99, and put > them into a list. > > import random > terms = [] > for i in range(2): > terms = random.randint(1, 99) All you're doing here is assigning an integer value to 'terms', twice. This assignment means 'terms' is no longer a list, but is now just an int. What you want is probably: terms.append (random.randint(1, 99)) > So I tried to change line 4 to the following: > terms += random.randint(1, 99) You can't freely mix types with python operators, i.e. a_list += an_int But you can use += with 2 ints or 2 lists, so you could do: terms += [random.randint(1, 99)] I think using append is much nicer though. > I understand this error thus: once an int has been placed into the list > terms, no further int can be added. But: terms is a mutable list, and NOT an > 'int' object! The int was never added to the list in the first place, because list += int is not something Python understands. > So here are my questions: what is the problem, and how can I generate two > random numbers and store them (preferably in a tuple)? I hope what I wrote above answers the first question. IIRC tuples are immutable, so you either to create the list first and then convert it to a tuple: terms_tuple = tuple(terms) Or you can create a tuple from the beginning (without a loop): terms_tuple = (random.randint(1, 99), random.randint(1, 99)) HTH, benno ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
