How to do named capture in ruby

Question

I want to name the capture of string that I get from scan. How to do it?

"555-333-7777".scan(/(\d{3})-(\d{3})-(\d{4})/).flatten #=> ["555", "333", "7777"] 

Is it possible to turn it into like this

{:area => "555", :city => "333", :local => "7777" } 

or

[["555","area"], [...]] 

I tried

"555-333-7777".scan(/((?<area>)\d{3})-(\d{3})-(\d{4})/).flatten 

but it returns

[] 

Answer 1

You should use match with named captures, not scan

m = "555-333-7777".match(/(?<area>\d{3})-(?<city>\d{3})-(?<number>\d{4})/) m # => #<MatchData "555-333-7777" area:"555" city:"333" number:"7777"> m[:area] # => "555" m[:city] # => "333" 

If you want an actual hash, you can use something like this:

m.names.zip(m.captures).to_h # => {"area"=>"555", "city"=>"333", "number"=>"7777"} 

Or this (ruby 2.4 or later)

m.named_captures # => {"area"=>"555", "city"=>"333", "number"=>"7777"}