I assumed it to be a typo; i.e., it should say &quot;less than&quot;.<p>`takeWhile` is different to `filter` in that is returns the input list until some element matches the predicate, whereas `filter` returns all elements that match the predicate. For example, if the predicate is `(&lt; 5)` and the input was `[9, 2, 3, 6]`, then `takeWhile` would return an empty list, but `filter` would return `[2, 3]`.