Question

Can someone explain what is wrong with this code that I get an error. I want to print the primes between 3 and 11. eventually I want to find the 1000th prime for pset01.

Answer 1

here is my code

Answer 2

Explain the logic of this code. I see you're trying to do it recursively, but I need help to understand.

Answer 3

http://pastebin.com/XRvYy0zu

Here is a quick revision of your code. Take a look at the changes I made to it. You will be able to enter a number there and find it to be prime or not.

Answer 4

Thank you, I can see why your code would work mortir, but I'm curious what was wrong with mine.
Here is the logic

Answer 5

i get this traceback
http://dpaste.com/695033/

Answer 6

I know. what does this mean? what should I do to my code?

Answer 7

I still don't understand what you're trying to do. But this error message means you are trying to use the variable i before having given an initial value to it. You have to initialize i before the while loop.

Answer 8

But I said i = 3 -- first line.

Answer 9

Warning: I am *not* saying it's good programming style. I'm just explaining where does this error comes from.
Check this : http://www.saltycrane.com/blog/2008/01/python-variable-scope-notes/

You are using a variable named i inside a function, and another variable named i is defined in the global scope. If you want the interpreter to know that, inside the function, you are setting the global variable, you have to say it this way:
global i

If you do that, you have another error, not related to the first one:
TypeError: unsupported operand type(s) for +: 'int' and 'str'
Easy to fix by putting str() around i in the print statement.
After that the program seems to run: http://pastebin.com/VS8kYf56

Doesn't produce good results though.

Answer 10

sigh ... I know it somehow thinks 9 is prime.
Now this is my slightly better attempt using morfir's code -- explanation provided of course.
The only problem is, it refuses to find ith primes for i>100. otherwise, it works fine. heh -- the wonderful world of incompetent newbie programming...
please, can you explain what that error is.
How can I understand what these errors mean in general -- maybe if I can see visually the program running line by line...

Answer 11

wohooo... done it 7919
it was a small matter of increasing the recursion limit.
did everyone do that or just me?

Answer 12

http://docs.python.org/reference/executionmodel.html

don't think i tackled this one with recursion