Question

I’m trying to answer this question on a practice test:

Write a function, def eliminate(x, y), that copies all the elements of the list x except the largest value into the list y.

The best thing I could come up with is:

def eliminate(x, y):
    print(x)
    y = x
    big = max(y)
    y.remove(big)
    print(y)
def main():
    x = [1, 3, 5, 6, 7, 9]
    y = [0]
    eliminate(x, y)
main()

I don’t think that’ll cut it if a question like that comes up on my final, and I’m pretty sure I shouldn’t be writing a main function with it, just the eliminate one. So how would I answer this? (keep in mind this is an introductory course, I shouldn’t be using more advanced coding)

Answer 1

I’d probably do this:

def eliminate(x, y):
    largest = max(x)
    y[:] = [elem for elem in x if elem != largest]

This fills y with all the elements in x except whichever is largest. For example:

>>> x = [1,2,3]
>>> y = []
>>> eliminate(x, y)
>>> y
[1, 2]
>>> x = [7,10,10,3,4]
>>> eliminate(x, y)
>>> y
[7, 3, 4]

This assumes that by “copies” the question is asking for the contents of y to be replaced. If the non-maximal elements of x are to be appended to y, you could use y.extend instead.

Note that your version doesn’t handle the case where there are multiple elements with the maximum value (e.g. [1,2,2]) — .remove() only removes one of the arguments, not all of them.