如何删除 Elixir 中列表的“任何”元素

Question

我有一个清单清单

>> list = [[1,""],[2,"b"],[3,""],[4,"c"]]

我想删除包含“”元素的列表

>>list = [[2,"b"],[4,"c"]]

我正在尝试寻找类似的东西

list = List.delete(list,[any,""])

Answer 1

您可以合并Enum.reject/2并Enum.member?/2拒绝任何包含空字符串的列表

iex> Enum.reject([[1,""],[2,"b"],[3,""],[4,"c"]], &Enum.member?(&1, ""))
[[2, "b"], [4, "c"]]

如果您的内部列表始终是相同的双项样式，并且您只想检查第二项，则还可以使用匿名函数

iex> Enum.reject([[1,""],[2,"b"],[3,""],[4,"c"]], fn [_, b] -> b == "" end)
[[2, "b"], [4, "c"]]

或者做几乎同样事情的理解

iex> for [a, b] when b != "" <- [[1,""],[2,"b"],[3,""],[4,"c"]], do: [a, b]
[[2, "b"], [4, "c"]]