遍历python中的列表和嵌套列表

my_list = [1, 2, 3, 4, 5]
for item in my_list:
    print(item)

nested_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
for sublist in nested_list:
    for item in sublist:
        print(item)

nested_list = [[1, 2, 3], [], [4, 5]]

for sublist in nested_list:
    if len(sublist) > 0:
        for item in sublist:
            print(item)

my_list = ['a', 'b', 'c']
for index, value in enumerate(my_list):
    print(f'Index: {index}, Value: {value}')

nested_list = [['a', 'b'], ['c', 'd']]
for i, sublist in enumerate(nested_list):
    for j, item in enumerate(sublist):
        print(f'Index: ({i}, {j}), Value: {item}')