creating a list during program execution.

[ichabod801]

Totally. Very common operation:

# file to list
data = open('data_file.txt').readlines()

# string to list
text = input('Type in a sentence: ')
words = text.split()

# build from numbers
fib = [1, 1]
for index in range(100):
    fib.append(fib[-1] + fib[-2])