lecture 07

lectures/07/lec7.erl

@@ -0,0 +1,47 @@
+-module(lec7).
+-export([fact/1, qsort/1, fizzbuzz/1, dedup/1]).
+
+fact(N) when N =< 0 -> 1;
+fact(N) -> N fact(N - 1).
+
+qsort([]) -> [];
+qsort([H | T]) ->
+	qsort([X || X <- T, X =< H]) ++ [H] ++ qsort([X || X <- T, X > H]).
+
+fizzbuzz(N) -> fizzbuzz(1, N);
+fizzbuzz(I, N) when I > N -> ok;
+fizzbuzz(I, N) ->
+	% ~n is newline in erlang, not \n
+	if
+		I rem 15 == 0 -> io.format("fizzbuzz~n");
+		I rem 5 == 0 -> io.format("buzz~n");
+		I rem 3 == 0 -> io.format("fizz~n");
+		true -> io.format("~p~n", [I])
+	end,
+	fizzbuzz(I + 1, N).
+
+dedup([]) -> [];
+dedup([X, X | R]) -> dedup([X|R]);
+dedup([X|R]) -> [X | dedup(R)].
+
+dedup2(L) ->
+	case L of
+		[] -> [];
+		[X, X | R] -> dedup2([X|R]);
+		[X | R] -> [X | dedup2(R)]
+	end.
+
+% compile
+% c(lec7)
+% lec7:fact(100)
+% lec7:qsort([3,2,7,6,8])
+
+F = fun(X) -> X * X end.
+lists:map(F, [1,3,2]).
+lists:map(fun string:length/1, ["hello", "goodbye"]).
+
+% accessing maps
+
+M = #{"bart" => 77, "homer" => 25}.
+#{"homer" := X} = M.
+X.