[ 1, 2, 3, 4, 5]
|> Enum.map(&(&1 * &1))
|> Enum.with_index
|> Enum.map( fn {value, index} -> value - index end )
|> IO.inspect        #=> [ 1, 3 ,7, 13, 21 ]#第一个map函数接受原始列表并生成一个新列表，其元素值是原来的平方。...如此下去最终生成了四个列表s = Stream.map [ 1, 3, 5, 7 ], &(&1 + 1)     #s不是一个列表
Enum.to_list s        #这样使用 => [ 2, 4, 6 ,8 ]#我们通常这样写
[ 1, 2, 3, 4 ]
|> Stream.map(&(&1 * &1))
|> Stream.map(&(&1 + 1))
|> Stream.filter( fn x -> rem(x, 2) == 1 end )            #rem求余
|> Enum.to_list        #转化为我们可见的    

Stream.cycle(~w{ green white })
|> Enum.take(5)        #green white green white green

Stream.iterate(0, &(&1 + 1)) |> Enum.take(5)        #[ 0, 1, 2, 3, 4]

Stream.unfold({0 ,1}, fn (f1, f2) -> {f1, {f2, f1 + f2}} end )
|> Enum.take(8)#[ 0, 1 ,1, 2, 3, 5, 8, 13 ]

Stream.resource(fn -> File.open("sample") end, fn file -> case IO.read(file, :line) doline when is_binary(line) -> { [line], file }_ -> { :halt, file }endend,fn file -> File.close!(file) end )

for x <- [1, 2, 3, 4, 5], do: x * xfor x <- [1, 2, 3, 4, 5], x < 4, do: x * x

for x <- [1, 2], y <- [5, 6], do: {x, y}        #[ {1, 5}, {1, 6}, {2, 5}, {2, 6} ]

min_maxes = [{1, 4}, {2, 3}, {10, 15}]
for {min, max} <- min_maxes, n <- min..max, do: n#[1, 2, 3, 4, 2, 3 ,10, 11, 12, 13, 14, 15]

first8 = [1, 2, 3, 4, 5, 6, 7, 8]
for x <- first8, y <- first8, x >= y, rem(x*y, 10) == 0, do: {x, y}　　　　#x >= y 防止出现{2, 5}、{5, 2}

for << ch <- "hello >>, do: ch        #返回的是列表[104, 101, 108, 108, 111]  iex显示为 'hello'
for << ch <- "hello" >>, do: <<ch>>        #将编码转换为字符串  ["h", "e", ... ]

for x <- ~w{ cat dog }, into: Map.new, do: { x, String.upcase(x) }        # %{"cat" => "CAT", "dog" => "DOG" }