Regex Multi Capture Groups

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1

Regex Question: Given following string: "default via 10.141.23.1 dev eth0 \n10.141.23.0/24 dev eth0 proto kernel scope link src 10.141.23.235 \n169.254.169.254 dev eth0 \n172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 \n"

I want to retrieve the following result: %{"default" => "10.141.23.1", "docker0" => "172.17.0.1"}

I can retrieve separately, like this: ~r/default via (?<default>\d+\.\d+\.\d+\.\d+)/ |> Regex.named_captures(str)

and ~r/dev docker0 proto kernel scope link src (?<docker0>\d+\.\d+\.\d+\.\d+)/ |> Regex.named_captures(str)
But I am not able to retrieve the desired result by combining both into one regex

e.g.

~r/default via (?<default>\d+\.\d+\.\d+\.\d+).*dev docker0 proto kernel scope link src (?<docker0>\d+\.\d+\.\d+\.\d+)/ |> Regex.named_captures(str)

returns nil

2

It is because by default, regular expressions treat newline characters in a special way. In your case, you’ll have to add the dotall option (sigil flag s) to ensure that the .* part between your two regular expression parts will not fail when a \n is reached:

r6 = ~r{default via (?<default>\d+\.\d+\.\d+\.\d+).+dev docker0 proto kernel scope link src (?<docker0>\d+\.\d+\.\d+\.\d+)}s
Regex.named_captures(r6, str)
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