Chapter 2: Types and Functions
p39-2: Write a function, lastButOne, that returns the element before the last.
- -- file ch02/lastButOne.hs
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lastButOne xs = if length xs == 2
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then head xs
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else lastButOne (tail xs)
tips: function length tells us how many elements are in a list;
function head returns the first element of a list;
function tail returns all but the head of a list, that is, a sub-list.
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