'''lecture_17_nested_loops.py
Demonstrate using nested lists
Oliver W. Layton
CS 151: Computational Thinking: Visual Media
Spring 2021
'''


'''
Visiting every item in a list with sublists
'''
# How can we access and replace every item in `digits`
# with 10 times the number?
digits = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

# What is len(digits)?
# print(len(digits))

# If we loop thru, what type of data is digits[i]?
# print(digits[0])

# To visit each int, as we loop through the list,
# let's start looping thru the sublist and print each item.
# for i in range(len(digits)):
#     currSublist = digits[i] # giving sublist an actual name.
#     for j in range(len(currSublist)): # same as below

# for i in range(len(digits)):
#     # print(digits[i])
#     print('Starting inner loop. i = ', i)
#     for j in range(len(digits[i])): # get length of current sublist
#         print(digits[i][j])
#     print('Ending inner loop. i = ', i)

# Now let's tackle the problem of replacing each number with 10 times
# the amount.
for i in range(len(digits)):
    for j in range(len(digits[i])): # get length of current sublist
        digits[i][j] = 10*digits[i][j]

print(digits)

# What values do `i` and `j` take on while iterating thru the nested loop?
# Let's print the see
for i in range(len(digits)):
    for j in range(len(digits[i])): # get length of current sublist
        print('i = ', i, 'j = ', j)