re = /(?!<[^>]*?>)\bhello world\b(?![^<]*?(?:<\/[^\/]*>|>))/
str = 'one two three hello world four five
one <a href=\'index.html\'> hello world </a> four five
foo bar <p>hello world</p> hello
<p name="hello world">hello world</p>
one two three <img alt=\'hello world\' \\>four five
<img alt="hello world"> foo
foo bar <a href="index.html">hello world</a> again
one two three hello world four five
one two three <img alt=\'hello world\' \\>four five'
# 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