names

        # MatchData.names

(from ruby core)
---
    mtch.names   -> [name1, name2, ...]

---

Returns a list of names of captures as an array of strings. This is the
same as mtch.regexp.names.

    /(?<foo>.)(?<bar>.)(?<baz>.)/.match("hoge").names
    #=> ["foo", "bar", "baz"]

    m = /(?<x>.)(?<y>.)?/.match("a") #=> #<MatchData "a" x:"a" y:nil>
    m.names                          #=> ["x", "y"]