PYTHON

Sorting a list using a named function

ex_lst = ['hi', 'how are you', 'bye', 'apple', 'zebra', 'dance']

def second_let(x):

    lst= []
    for wrd in x:
        lst.append(wrd[1])
    return lst

print(second_let(ex_lst))
print(sorted(second_let(ex_lst)))

sorted_by_second_let= sorted(ex_lst, key= second_let)

python sort a list using defined order

>>> A = [[3,5],[1,3],[6,1]]
>>> B = [6,1,3]
>>> srt = {b: i for i, b in enumerate(B)}
>>> sorted(A, key=lambda x: srt[x[0]])
[[6, 1], [1, 3], [3, 5]]

python sort a list using defined order

>>> sorted(A, key = lambda i: B.index(i[0]))
[[6, 1], [1, 3], [3, 5]]