primes.py

## I'm going to start my comments with ## to distiguish them.


number = 1
## I'd make this a function which returns True or False
## Before you were always returning a list of length 1 or 0, which isn't
## that helpful.  Remember, just because you name your variable `primes`
## here doesn't mean that it affects the variable named `primes` below.
def is_prime(number):
    factors = []
    #determine if prime
    for num in range(1, number+1):
        #for each whole number less than the input number
        #divide the input number my it. If the remainder is 0, add to
        #a list of factors. Else, ignore it.
        if number % num == 0:
            factors.append(num)
        ## You can drop the else: pass, it doesn't do anything
    #If the list of factors is only 1 and the number, add the number
    #to a list of primes (not working for some reason)
    ## if factors == [1, number]:
    ##     primes.append(number)

    ## We can just return the condition directly.
    return factors == [1, number]

## Now I can test this in the terminal interactively
## $ python -i primes.py
## >>> is_prime(5)
## True
## >>> is_prime(6)
## False


## We really don't need this at all, but yes it's correct.
def increase_number(number):
    #increases input number by one (works fine)
    number = number + 1
    return number



## To make interactive use easier, I like using this pattern of naming
## all my functions, and then just calling the main one.
def main():
    primes = []
    nth_prime = int(input('please type the nth prime you want: '))
    print("Trying to find the {}th prime".format(nth_prime))
    ## I had to define `number` here, since we use it inside the loop
    ## Remember that variables defined in other functions are not visible
    ## here.
    number = 2
    while True:
        ## Now that `is_prime` just returns a boolean, it's easy
        ## to use it in a if.
        if is_prime(number):
            print("{} is prime".format(number))
            primes.append(number)
        number = increase_number(number)
        if len(primes) == nth_prime:
            print(primes[-1])
            break

main()