re = /cat(?:(?!bird|cat).)*dog(?:(?!dog|bird).)*bird/m
str = 'cat abcd
abc <dog abc
</bird>
cat abcd
abc </bird> abc
<dog
catabcd
abc <dog abc
</bird>
cat abcd
</bird>
<dog
<dog
cat
</bird>
match: cat dog bird
match, so we have: cat dog bird, cat dog dog bird, and cat dog cat bird should all
not match first cat: cat cat dog bird
not match second dog: cat dog dog bird
not match lsat bird: cat dog bird bird'
# 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