List comprehension is not whatever you're doing there. An example of list comprehension:
list = [value*2 for value in range(1, 20)]
See, list comprehension is used to make a list from an existing list. The value of the new list is defined by a function. In this case, the value of a will be 2,4,6, etc.
Your current syntax list[...], is trying to access an element of a list.