Retrieve the two highest item from a list containing 100,000 integers

Question

How can retrieve the two highest item from a list containing 100,000 integers without having to sort the entire list first?

Answer 1

Sort the list, and if list is not null, extract last two element

>>> a=[0,6,8,5,10,5]
>>> a.sort()
>>> a
[0, 5, 5, 6, 8, 10]
>>> if a:
...  print a[-1],a[-2]
... 
10 8

Simple and most efficient:)

Now if sorting is not required, find max, remove max, find max again

>>> a=[0,6,8,5,10,5]
>>> max(a)
10
>>> a.remove(max(a))
>>> max(a)
8
>>> 

Of course, you will lose the original list but you can create a temporary list as well.