flatten list of lists of lists to a list of lists

Question

I\'ve already searched SO for how to flatten a list of lists (i.e. here:Making a flat list out of list of lists in Python) but none of the solutions I find addresses flatten

Answer 1

For this particular case,

In [1]: [sum(x,[]) for x in my_list]
Out[1]: [[1, 2, 3, 4, 5], [9, 8, 9, 10, 3, 4, 6], [1]]

is the shortest and the fastest method:

In [7]: %timeit [sum(x,[]) for x in my_list]
100000 loops, best of 3: 5.93 µs per loop