When it is required to find the starting index of all nested lists, a simple iteration along with the ‘append’ method is used.
Example
Below is a demonstration of the same
my_list = [[51], [91, 22, 36, 44], [25, 25], [46, 67, 78,82, 69, 29], [ 7, 5]]
print("The list is :")
print(my_list)
my_result = []
my_len = 0
for sub in my_list:
my_result.append(my_len)
my_len += len(sub)
print("The initial element indices are :")
print(my_result)Output
The list is : [[51], [91, 22, 36, 44], [25, 25], [46, 67, 78, 82, 69, 29], [7, 5]] The initial element indices are : [0, 1, 5, 7, 13]
Explanation
A list of list is defined and is displayed on the console.
An empty list is defined, and an integer is assigned to 0.
The list is iterated over, and the integer is appended to the empty list.
The integer is incremented based on element in the list.
This empty list which is now populated is the result.
It is displayed as output on the console.