python nested list code example

Example 1: python nested list

# example of a nested list
my_list = [[1, 2], ["one", "two"]]

# accessing a nested list
my_list[1][0] # outputs "one"

Example 2: how to make one list from nested list

>>> from collections import Iterable
def flatten(lis):
     for item in lis:
         if isinstance(item, Iterable) and not isinstance(item, str):
             for x in flatten(item):
                 yield x
         else:        
             yield item

>>> lis = [1,[2,2,2],4]
>>> list(flatten(lis))
[1, 2, 2, 2, 4]
>>> list(flatten([[1, 2, 3], [4, 5, 6], [7, 8, 9]]))
[1, 2, 3, 4, 5, 6, 7, 8, 9]

Example 3: python nested list

L = [[1, 2, 3],[4, 5, 6],[7, 8, 9]]   
for list in L:
    for number in list:
        print(number, end=' ')
# Prints 1 2 3 4 5 6 7 8 9