re = /@(?=([\w.@-]*\w))\1(?!\[\d+\])/m
str = 'Hello @kevin
Hello @kevin.
Hello @kevin[1].
Hello @kev._in[1].'
# Print the match result
str.scan(re) do |match|
puts match.to_s
end
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html