Three different approaches for flattening a list of list in Python
- input: [[1,2,3], [3,4,5]]
- output: [1,2,3,3,4,5,]
list_of_list = [[1,2,3], [3,4,5]] # 1st approach: using for loops flattened_list = list() for sub_list in list_of_list: for item in sub_list: flattened_list.append(item) # 2nd approach: using single line for loops flattened_list = [item for sub_list in list_of_list for item in sub_list] # 3rd approach: using lambda function if you do many of # these operations for different list of list flatten = lambda list_of_list: [item for sub_list in list_of_list for item in sub_list] flattened_list = flatten(list_of_list) # if you have many list of list to flatten, such as list_of_list1, list_of_list2 flattened_list1 = flatten(list_of_list1) flattened_list2 = flatten(list_of_list2)