python query - function arguments are incorrect type?

i'm pretty new to python and i'm having trouble with passing an argument into the random.choice function.

basically i'm trying to write a loop that will start off by selecting a random letter(which are all names of other lists) from the 'a' list, then input the selected letter into random.choice again to generate a sequence of random letters.

unfortunately the second call to random.choice isn't working, it just keeps repeating the inputted letter instead of pointing to a new list. any ideas how to fix this? i've been looking online for a few hours but can't find any 开发者_Python百科similar problems/solutions. any help would be much appreciated!

import random

a = ['b','c','d']
b = ['a','e']
c = ['a','d','f']
d = ['a','c','e','f','g','h']
e = ['b','d','h']
f = ['c','d','g','i']
g = ['d','f','i']
h = ['d','e','g','i']
i = ['f','h']

x = 0
answer = random.choice(f)
print "answer is %s " % answer

while x < 5:
    answer2 = random.choice(answer) 
    print "answer2 is now %s " % answer2
    x = x + 1

You've fallen into the common beginner's trap of mixing up variables and data, and trying to treat your code as data. You shouldn't typically try to do that - don't put the name of a variable into another variable and try to access it that way.

Instead, keep all the data together in a data structure, and just use your variables to access that structure, like this:

import random

DATA = {
    'a': ['b','c','d'],
    'b': ['a','e'],
    'c': ['a','d','f'],
    'd': ['a','c','e','f','g','h'],
    'e': ['b','d','h'],
    'f': ['c','d','g','i'],
    'g': ['d','f','i'],
    'h': ['d','e','g','i'],
    'i': ['f','h'],
}

x = 0
answer = random.choice(DATA['f'])
print "answer is %s " % answer

while x < 5:
    answer2 = random.choice(DATA[answer]) 
    print "answer2 is now %s " % answer2
    x = x + 1

Well... one issue is that you're always getting answer2 from the same list, since you're not doing any other assignments...

Just suppose x == 'c'. Then the second call to random.choice is actually

answer2 = random.choice('c')

This is like selecting a letter from a list containing only 'c'. This is NOT equivalent to the following:

answer2 = random.choice(c)

You need to convert the string 'c' into a list referenced by the variable c.

This mapping may work:

values = {
    "a": a, "b": b, "c": c, "d": d, "e": e,
    "f": f, "g": g, "h", h, "i": i, "j": j,
    }

Then values['c'] is the list referenced by variable c