What would be the most elegant/pythonic way of achieving: "if x% of total values in a list are greater than the y, return true". I have currently implemented a function:
def check(listItems, val):
'''A method to check all elements of a list against a given value.
Returns true if all items of list are greater than value.'''
return all(x>val for x in listItems)
But for my use case, waiting for this particular condition is quite costly and somewhat useless. I would want to proceed if ~80% of the items in list are greater than the given value. One approach in my mind is to sort the list in descending order, create another list and copy 80% of the elements of list to the new list, and run the function for that new list. However, I am hoping that there must be a more elegant way of doing this. Any suggestions?
It sounds like you are dealing with long lists which is why this is costly. If would be nice if you could exit early as soon as a condition is met. any() will do this, but you'll want to avoid reading the whole list before passing it to any(). One options might be to use itertools.accumulate to keep a running total of True values and the pass that to any. Something like:
from itertools import accumulate
a = [1, 2, 2, 3, 4, 2, 4, 1, 1, 1]
# true if 50% are greater than 1
goal = .5 * len(a) # at least 5 out of 10
any( x > goal for x in accumulate(n > 1 for n in a))
accumulate won't need to read the whole list — it will just start passing the number of True values seen up to that point. any should short-circuit as soon as it finds a true value, which in the above case is at index 5.