List Iteration in Python

Question

So i get this error:

TypeError: list indices must be integers, not str

pointing to this line of code:

if snarePattern[i] == '*':

whenever I use what I thought was simple Python

snarePattern = ['-', '*', '-', '*']
for i in snarePattern:
    if snarePattern[i] == '*':
        ...

Is this not allowed? What don't I know?

And also, If anyone knows where I'm going with this code, can you think of an easier way to create and parse simple patterns like this??? I'm new to Python.

Thanks guys

Answer 1

for i in snarePattern: goes through each item not each index:

>>> snarePattern = ['-', '*', '-', '*']
>>> for c in snarePattern:
        print c


-
*
-
*

You can change it to

for i in range(len(snarePattern)):

if you really need it, but it looks like you don't, just check if c == '*' for example.

A better way to go through indices is

for i, c in enumerate(snarePattern):  # i is each index, c is each character