Sorted function in python

Question

I have written a program which must sort the following:

unsorted_list=[['le', 5], ['aab', 4], ['aaa', 5]]

to:

[['aaa', 5], ['le', 5], ['aab', 4]]

It should be sorted by number. If the numbers are the same then it should sort alphabetical. I have the following code:

def sortItem(lista):
    ''' func for sort by item'''
    return lista[1]
sorted(unsorted_list, key=sortItem, reverse=True)

Unfortunately, it does not return string alphabetical. Any suggestion how to do it?

Answer 1

Since x[1] is an integer, you can sort it from maximum to minimum simply by negating it:

sorted(unsorted_list, key=lambda x: (-x[1], x[0]))

The tuples created in key will be sorted according to the first element ( -x[1] ), then by second element ( x[0] ). This corresponds exactly to your logic:

"So, it means than it is sorted by number but if numbers are the same the sort will be alphabetical."

Answer 2

In [2]: l = [['le', 5], ['aab', 4], ['aaa', 5]]

In [3]: sorted(l, key=lambda (x,y):(-y,x))
Out[3]: [['aaa', 5], ['le', 5], ['aab', 4]]

Answer 3

If someone is not familiar with the lambda function, here is how to break this down by defining your own function from the scratch -

unsorted_list=[['le', 5], ['aab', 4], ['aaa', 5]]
def num_and_alpha(tuple):
    return (-tuple[1], tuple[0])

print sorted(unsorted_list, key=num_and_alpha)