How to find specific matches in a string using regex

Question

I have strings like

View_Export_US_Horizontals_Ultimate_DirectionalSurveys

I want to extract matches like

[["US_Horizontals", "Ultimate", "DirectionalSurveys"]] //String Ultimate may or may not be present

I have the following RegEx, /^View_Export_(US\_(GoM|Horizontals|Onshore))((_Ultimate)?)_(\w+)/

but i get the following matches array

[["US_Horizontals", "Horizontals", "_Ultimate", "_Ultimate", "DirectionalSurveys"]]

How do i skip strings like Horizontals & _Ultimate and just get an array like

[["US_Horizontals", "Ultimate", "DirectionalSurveys"]]

Or

[["US_Horizontals", "DirectionalSurveys"]]

Answer 1

You can use

\AView_Export_(US_(?:GoM|Horizontals|Onshore))(?:_(Ultimate))?_(\w+)

See the regex demo. Details:

• \A - start of string (^ in Ruby regex means start of any line)
• View_Export_ - a fixed string
• (US_(?:GoM|Horizontals|Onshore)) - Group 1: US_ string and then either GoM, Horizontals or Onshore words
• (?:_(Ultimate))? - an optional sequence of an underscore and an Ultimate word
• _ - an underscore
• (\w+) - Group 3: any one or more word chars.

See the Ruby demo:

string = "View_Export_US_Horizontals_Ultimate_DirectionalSurveys"
rx = /\AView_Export_(US_(?:GoM|Horizontals|Onshore))(?:_(Ultimate))?_(\w+)/
one, two, three = string.match(rx).captures

puts one   #=> US_Horizontals
puts two   #=> Ultimate
puts three #=> DirectionalSurveys