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I'm just learning Python. I've created a simple coin flipper program 
here is the code:
[source]
#Coin flipper
import random
heads = 0
tails = 0
counter = 0
coin = random.randrange(2)
while (counter < 100):
if (coin == 0):
heads += 1
counter += 1
else:
tails += 1
counter += 1
coin = random.randrange(2)
print "\nThe coin landed on heads", heads, "times."
print "\nThe coin landed on tails", tails, "times."
[/source]
<<<I'm sure the [source] tags don't work  I through them in there
anyway.>>>
The program runs  however  it will give me 100 heads OR 100 tails.
Can someone spot the logic error?
Thanks
~Dan  
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On Tue, 20060221 at 16:14 0800, DannyB wrote: I'm just learning Python. I've created a simple coin flipper program  here is the code:
[source] #Coin flipper import random
heads = 0 tails = 0 counter = 0
coin = random.randrange(2)
while (counter < 100): if (coin == 0): heads += 1 counter += 1 else: tails += 1 counter += 1
coin = random.randrange(2)
print "\nThe coin landed on heads", heads, "times." print "\nThe coin landed on tails", tails, "times." [/source]
<<<I'm sure the [source] tags don't work  I through them in there anyway.>>>
The program runs  however  it will give me 100 heads OR 100 tails. Can someone spot the logic error?
Yes. Put coin = random.randrange(2) inside the while loop.
import random
heads = 0
tails = 0
counter = 0
coin = random.randrange(2)
while (counter < 100):
if (coin == 0):
heads += 1
counter += 1
else:
tails += 1
counter += 1
coin = random.randrange(2)
print "\nThe coin landed on heads", heads, "times."
print "\nThe coin landed on tails", tails, "times."

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DannyB wrote: I'm just learning Python. I've created a simple coin flipper program  here is the code:
[source] #Coin flipper import random
heads = 0 tails = 0 counter = 0
while (counter < 100):
coin = random.randrange(2)
Claudio
if (coin == 0): heads += 1 counter += 1 else: tails += 1 counter += 1
coin = random.randrange(2)
print "\nThe coin landed on heads", heads, "times." print "\nThe coin landed on tails", tails, "times." [/source]
<<<I'm sure the [source] tags don't work  I through them in there anyway.>>>
The program runs  however  it will give me 100 heads OR 100 tails. Can someone spot the logic error?
Thanks
~Dan  
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DannyB wrote: I'm just learning Python. I've created a simple coin flipper program  here is the code:
[source] #Coin flipper import random
heads = 0 tails = 0 counter = 0
coin = random.randrange(2)
while (counter < 100): if (coin == 0): heads += 1 counter += 1 else: tails += 1 counter += 1
coin = random.randrange(2)
print "\nThe coin landed on heads", heads, "times." print "\nThe coin landed on tails", tails, "times." [/source]
<<<I'm sure the [source] tags don't work  I through them in there anyway.>>>
The program runs  however  it will give me 100 heads OR 100 tails. Can someone spot the logic error?
Thanks
~Dan
Looks an awful lot like your homework, but I'll give you a clue.
You need to get the your coin tosses inside your loop. Otherwise
you only toss the coin once and then loop 100 times with the
same value.
Larry Bates  
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DannyB wrote: I'm just learning Python. I've created a simple coin flipper program  here is the code:
[source] #Coin flipper import random
heads = 0 tails = 0 counter = 0
coin = random.randrange(2)
while (counter < 100): if (coin == 0): heads += 1 counter += 1 else: tails += 1 counter += 1
coin = random.randrange(2)
print "\nThe coin landed on heads", heads, "times." print "\nThe coin landed on tails", tails, "times." [/source]
<<<I'm sure the [source] tags don't work  I through them in there anyway.>>>
The program runs  however  it will give me 100 heads OR 100 tails. Can someone spot the logic error?
Thanks
~Dan
Dan,
Looping is easier with:
for x in range(100):
if random.randint(0,1) == 0:
heads += 1
else:
tails += 1
Inside the loop you need to "flip" on each pass.
You're "flipping" once before the start of the loop now.
wes  
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DannyB wrote: I'm just learning Python.
So am I :)
I've created a simple coin flipper program  here is the code:
[source] #Coin flipper import random
heads = 0 tails = 0 counter = 0
coin = random.randrange(2)
while (counter < 100): if (coin == 0): heads += 1 counter += 1 else: tails += 1 counter += 1
coin = random.randrange(2)
This line is you logic error because it's not part of your while loop
the coin variables get the result of random.randrange(2) assigned only
one time (before the loop).
print "\nThe coin landed on heads", heads, "times." print "\nThe coin landed on tails", tails, "times." [/source]
<<<I'm sure the [source] tags don't work  I through them in there anyway.>>>
The program runs  however  it will give me 100 heads OR 100 tails. Can someone spot the logic error?
Thanks
~Dan
You could changed the program to this it works too and is just as
readable (IMHO):
#Coin flipper
import random
heads = 0
tails = 0
counter = 0
# removed random line
while (counter < 100):
if random.randrange(2): # put random here
heads += 1
counter += 1
else:
tails += 1
counter += 1
# removed random line
print "\nThe coin landed on heads", heads, "times."
print "\nThe coin landed on tails", tails, "times."
Take my advice with caution I'm also new to this :)
Btw, it is possible that the coins lands on it side if not catched with
the hand (yes I have seen it happen) ;)

mph  
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Thanks everyone for your insight.
I'm coming from C++  I'm used to formatting code with {} instead of
whitespaces.
@Larry  this isn't my homework :P I'm actually taking a VB.NET class
in school.
I was teaching myself C++ but decided to scale back to Python. I've
heard it was a bit easier to understand and it cuts your development
time by at least 50% (I've heard 90%).
Logically I can figure things out  its the formatting of the logic in
Python that is messing me up. I'll get it soon enough =)  
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wes weston wrote: Looping is easier with: for x in range(100): if random.randint(0,1) == 0: heads += 1 else: tails += 1
Also, with the functional programming tools of map, filter, and lambda,
this code can be reduced to just six lines:
import random
flips = map(lambda x: random.randrange(2), xrange(100))
heads = len(filter(lambda x: x is 0, flips))
tails = len(filter(lambda x: x is not 0, flips))
print "The coin landed on heads", heads, "times."
print "The coin landed on tails", tails, "times."  
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John Zenger wrote: Also, with the functional programming tools of map, filter, and lambda, this code can be reduced to just six lines:
import random
flips = map(lambda x: random.randrange(2), xrange(100)) heads = len(filter(lambda x: x is 0, flips)) tails = len(filter(lambda x: x is not 0, flips))
Or a filter/map/lambda free way:
heads = sum(random.randrange(2) for x in xrange(100))
tails = 100  heads  
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<bo****@gmail.com> wrote in message
news:11**********************@g43g2000cwa.googlegr oups.com... John Zenger wrote: Also, with the functional programming tools of map, filter, and lambda, this code can be reduced to just six lines:
import random
flips = map(lambda x: random.randrange(2), xrange(100)) heads = len(filter(lambda x: x is 0, flips)) tails = len(filter(lambda x: x is not 0, flips))
Or a filter/map/lambda free way:
heads = sum(random.randrange(2) for x in xrange(100)) tails = 100  heads
sort, then groupby.
import itertools
import random
h,t = [len(list(g)) for k,g in itertools.groupby(sorted([random.randrange(2)
for i in xrange(100)]))]
print h,t  
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wes weston wrote: DannyB wrote:
I'm just learning Python. I've created a simple coin flipper program 
....
Dan, Looping is easier with: for x in range(100): if random.randint(0,1) == 0: heads += 1 else: tails += 1
Or, continuing with that theme:
for x in range(N):
heads += random.randint(0, 1)
As in:
import random
N = 100
heads = 0
for x in range(N):
heads += random.randint(0, 1)
print "%d heads and %d tails." % (heads, N  heads)  
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DannyB said unto the world upon 21/02/06 06:14 PM: I'm just learning Python. I've created a simple coin flipper program  here is the code:
[source] #Coin flipper import random
heads = 0 tails = 0 counter = 0
coin = random.randrange(2)
while (counter < 100): if (coin == 0): heads += 1 counter += 1 else: tails += 1 counter += 1
coin = random.randrange(2)
<snip>
The program runs  however  it will give me 100 heads OR 100 tails. Can someone spot the logic error?
<snip>
Your original question is long since answered. But I've a style point.
As Dennis Lee Bieber pointed out, you don't need all three
accumulators. If you keep to the overall style of your code, you can
avoid repeating yourself as:
while (counter < 100):
counter += 1 # No point in putting this in each branch
coin = random.randrange(2)
if (coin == 0):
heads += 1
else:
tails += 1
For roughly the same style, I'd go with:
heads = 0
count = 100
for i in range(count):
if random.randrange(2):
heads += 1
tails = count  heads
HTH,
Brian vdB  
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"Paul McGuire" <pt***@austin.rr._bogus_.com> wrote in message
news:yU******************@tornado.texas.rr.com... <bo****@gmail.com> wrote in message news:11**********************@g43g2000cwa.googlegr oups.com...
sort, then groupby.
import itertools import random h,t = [len(list(g)) for k,g in
itertools.groupby(sorted([random.randrange(2) for i in xrange(100)]))] print h,t
By the way, sort + groupby generalizes beyond just coinflipping. Here is a
modified version that simulates die rolls.
 Paul
import itertools
import random
NUM_ROLLS = 1000
dieRolls = [random.randrange(6)+random.randrange(6)+2 for i in
xrange(NUM_ROLLS)]
# create dummy list entries for impossible rolls of 0 and 1
rolls = [None,None]
rolls += [len(list(g)) for k,g in itertools.groupby(sorted(dieRolls))]
# print out nice histogram
for i,r in enumerate(rolls):
if i > 1:
print "%2d  %s" % (i,"*"*int(round(r/10.0)))
prints:
2  ***
3  *****
4  *********
5  **********
6  ***************
7  ******************
8  **************
9  *********
10  *******
11  *******
12  ***   This discussion thread is closed Replies have been disabled for this discussion.   Question stats  viewed: 2469
 replies: 12
 date asked: Feb 22 '06
