return indexes of all regex occurrences in string in Ruby

Question

How do I obtain an array of the indexes (or positions) all occurrences of a regexp in a string?

example_string= "hello how are you?

I would like to obtain the array [1,12] for regexp /e/

Zoran · Accepted Answer · 2017-07-14 01:24:37Z

8

Here's one approach to get an array of indexes of matches:

example_string = "hello how are you?"

example_string.enum_for(:scan, /e/).map { Regexp.last_match.begin(0) }

# => [1, 12]

Hope it helps!

answered Jul 19, 2015 at 22:32

Zoran

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Comments

Cary Swoveland · Accepted Answer · 2015-07-20 01:20:12Z

4

This is a variant of @Zoren's excellent answer:

example_string = "hello how are you?"

example_string.gsub(/e/).with_object([]) { |_,a| a << Regexp.last_match.begin(0) }
 #=> [1, 12]

answered Jul 20, 2015 at 1:20

Cary Swoveland

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