Question

我正在尝试使用以下正则表达式

~r/(?<cmd>.*)(:(?<args>.*))?/

获取以下行为

"COMMAND:ARGS" => %{cmd: "COMMAND", args: "ARGS"}
"COMMAND" => %{cmd: "COMMAND", args: nil}

但我得到的只是

iex(66)> Regex.named_captures(~r/(?<cmd>.*)(:(?<args>.*))?/, "COMMAND:ARG")
%{"args" => "", "cmd" => "COMMAND:ARG"}
iex(67)> Regex.named_captures(~r/(?<cmd>.*)(:(?<args>.*))?/, "COMMAND")       
%{"args" => "", "cmd" => "COMMAND"}

我做错了什么？

Answer 1

See regex in use here

(?<cmd>[^:]+)(?::(?<args>.*))?
(?<cmd>[^:\n]+)(?::(?<args>.*))?   # for multiline content

(?<cmd>[^:\n]+)将除:或\n（在第二个版本中）之外的任何字符捕获到名为cmd
(?::(?<args>.*))?可选择匹配以下内容
- :按字面意思匹配
- (?<args>.*)将该行的其余部分捕获到名为args

结果：

Match 1
    Full match      0-12    `COMMAND:ARGS`
    Group `cmd`     0-7     `COMMAND`
    Group `args`    8-12    `ARGS`
Match 2
    Full match      13-20   `COMMAND`
    Group `cmd`     13-20   `COMMAND`

Elixir正则表达式组和？-mark

1 个答案: