Kinda newb-ish question

[ChocoboMog123]

What's wrong with line 8 in this code?
x=1
while 1==1:
x=x+1
y=range(1,x)
z=0
q=9
for count in y:
q=x%y
if q==0:
z=z+1
if z<1:
print x
It keeps giving me
Traceback (most recent call last):
File "C:\Python23\Prime Number.py", line 8, in -toplevel-
q=x%y
TypeError: unsupported operand type(s) for %: 'int' and 'list'

It's supposed to be a program to print out prime numbers.
If anyone knows of a program that does this or can write one, can you
show me the code? Thanks.

 

[Hans Nowak]

What's wrong with line 8 in this code?
x=1
while 1==1:
x=x+1
y=range(1,x)
z=0
q=9
for count in y:
q=x%y
if q==0:
z=z+1
if z<1:
print x
It keeps giving me
Traceback (most recent call last):
File "C:\Python23\Prime Number.py", line 8, in -toplevel-
q=x%y
TypeError: unsupported operand type(s) for %: 'int' and 'list'

The error message points out what's wrong with it... you're using the %
operator with an int (x) and a list (y), which is unsupported. You probably
mean something like x % count, although that doesn't make the algorithm work.

Quick tips: use range(2,x) rather than range(1,x), and x % count. An infinite
loop is probably not a good idea either.

HTH,

 

[Duncan Smith]

What's wrong with line 8 in this code?
x=1
while 1==1:
x=x+1
y=range(1,x)
z=0
q=9
for count in y:
q=x%y
if q==0:
z=z+1
if z<1:
print x
It keeps giving me
Traceback (most recent call last):
File "C:\Python23\Prime Number.py", line 8, in -toplevel-
q=x%y
TypeError: unsupported operand type(s) for %: 'int' and 'list'

The clue is in the traceback. 'y' is a list. Presumably you meant q = x %
count.

Duncan

 

[BW Glitch]

What's wrong with line 8 in this code?
x=1
while 1==1:

I think it would be better as:
while True:

x=x+1
y=range(1,x)
z=0
q=9
for count in y:
q=x%y

It should be:
q=x%count

if q==0:
z=z+1
if z<1:
print x
It keeps giving me
Traceback (most recent call last):
File "C:\Python23\Prime Number.py", line 8, in -toplevel-
q=x%y
TypeError: unsupported operand type(s) for %: 'int' and 'list'

It's supposed to be a program to print out prime numbers.
If anyone knows of a program that does this or can write one, can you
show me the code? Thanks.

As it points out, y is a list.


--
Glitch

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"Like you're three gigabytes of attitude on a two-gig hard drive. No
wonder they got personality problems!"
-- Cheetor and Rhinox, "Dark Designs"

 

[Mark Dufour]

What's wrong with line 8 in this code?
x=1
while 1==1:
x=x+1
y=range(1,x)
z=0
q=9
for count in y:
q=x%y
if q==0:
z=z+1
if z<1:
print x
It keeps giving me
Traceback (most recent call last):
File "C:\Python23\Prime Number.py", line 8, in -toplevel-
q=x%y
TypeError: unsupported operand type(s) for %: 'int' and 'list'

It's supposed to be a program to print out prime numbers.
If anyone knows of a program that does this or can write one, can you
show me the code? Thanks.

Sure. The expression range(1,x) produces a list, not a number. So y is a list,
and x%y now tries to perform a modulo operation with a list as modulo number!

Instead of using z, you might also use a boolean, or True/False variable,
perhaps like this:

x=1

while 1:
x += 1
prime = True
for y in range(2,x):
if x%y == 0:
prime = False
break
if prime: print x

Notice the (2,x) instead of (1,x). You don't want to test for division by 1..

Of course, finding primes this way by trial division is a very slow method..
A simple optimization would be to only try numbers up to the square root of
x.


Mark Dufour.

 

[David M. Wilson]

(e-mail address removed) (ChocoboMog123) wrote...

It's supposed to be a program to print out prime numbers.
If anyone knows of a program that does this or can write one, can you
show me the code? Thanks.

Have you tried Google? Python code is lovely and verbose, and that
makes it fun to google for. Try: "def isPrime" +python

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/149148
http://mail.python.org/pipermail/python-list/2002-May/102160.html

Etc.


David.

 

[Harald Massa]

File "C:\Python23\Prime Number.py", line 8, in -toplevel-

An infinite loop is probably not a good idea either.

Why should it not be a good idea? Are there any ideas that the number of
primes is limited?




Harald

 

[ChocoboMog123]

Thanks for the help everyone. Worked out fine when I changed it.

 

[Hans Nowak]

File "C:\Python23\Prime Number.py", line 8, in -toplevel-



Why should it not be a good idea? Are there any ideas that the number of
primes is limited?

No, but the program will never finish, which doesn't make it very useful
except for staring at its output while eating tons of pretzels and listening to
The Orb.