Scala performance question

Question

In the article written by Daniel Korzekwa, he said that the performance of following code:

list.map(e => e*2).filter(e => e>10)

is muc

Answer 1

Basically it's traversing a list twice. Once for multiplying every element with two. And then another time to filter the results.

Think of it as one while loop producing a LinkedList with the intermediate results. And then another loop applying the filter to produce the final results.

This should be faster:

list.view.map(e => e * 2).filter(e => e > 10).force