请100_000
在Iex中默认启用千位数分组(例如).如果是的话真的很有帮助.
否则我们如何指定它IO.puts
?
根据您的描述,没有启用数字分组的本机选项Inspect.Opts
.
但是,以下应该工作覆盖使用时检查的行为IEx
与Integer
和Float
,如果你把它放在你的本地~/.iex.exs
文件:
defmodule PrettyNumericInspect do
def group(value, :binary, true),
do: value |> group_by(8)
def group(value, :decimal, true),
do: value |> group_by(3)
def group(value, :hex, true),
do: value |> group_by(2)
def group(value, :octal, true),
do: value |> group_by(4)
def group(value, _, _),
do: value
defp group_by(value, n) when byte_size(value) > n do
size = byte_size(value)
case size |> rem(n) do
0 ->
(for << << g :: binary-size(n) >> <- value >>,
into: [],
do: g)
|> Enum.join("_")
r ->
{head, tail} = value |> String.split_at(r)
[head, group_by(tail, n)] |> Enum.join("_")
end
end
defp group_by(value, _),
do: value
end
defimpl Inspect, for: Float do
def inspect(thing, %Inspect.Opts{pretty: pretty}) do
[head, tail] = IO.iodata_to_binary(:io_lib_format.fwrite_g(thing))
|> String.split(".", parts: 2)
[PrettyNumericInspect.group(head, :decimal, pretty), tail]
|> Enum.join(".")
end
end
defimpl Inspect, for: Integer do
def inspect(thing, %Inspect.Opts{base: base, pretty: pretty}) do
Integer.to_string(thing, base_to_value(base))
|> PrettyNumericInspect.group(base, pretty)
|> prepend_prefix(base)
end
defp base_to_value(base) do
case base do
:binary -> 2
:decimal -> 10
:octal -> 8
:hex -> 16
end
end
defp prepend_prefix(value, :decimal), do: value
defp prepend_prefix(value, base) do
prefix = case base do
:binary -> "0b"
:octal -> "0o"
:hex -> "0x"
end
prefix <> value
end
end
必须将该Inspect.Opts
选项:pretty
设置true
为才能显示数字分组.根据IEx.configure/1
相当检查的文档应该默认启用.
启动时iex
,你会看到2个警告重新界定Inspect.Float
和Inspect.Integer
,但它应该继续像正常工作算账:
iex> 100_000
100_000
iex> 100_000.1
100_000.1
它还支持不同的分组:base
选项(:binary
,:decimal
,:octal
和:hex
):
iex> inspect 0b11111111_11111111, base: :binary, pretty: true
"0b11111111_11111111"
iex> inspect 999_999, base: :decimal, pretty: true
"999_999"
iex> inspect 0o7777_7777, base: :octal, pretty: true
"0o7777_7777"
iex> inspect 0xFF_FF, base: :hex, pretty: true
"0xFF_FF"