Question

I have an array with keywords and I have a string, which may contain those keywords. I now need to know how many keywords are in the given string:

keywords = [ 'text' ,'keywords' ,'contains' ,'blue', '42']
text = 'This text is not long but it contains 3 keywords'

How can I now find out with a ruby command how many of the strings in my array are in the text (three in this case)? I could of course use a for each loop but I am almost sure that there is a more concise way to achieve this.

Thanks for your help

Update: Preferably the solution should not rely on the spaces. So the spaces could be replaced by arbitrary characters.

Update 2: The command should look for unique occurrences.

Answer 1

Here’s one approach:

text.scan(/#{keywords.join('|')}/).length

Note that this is safe only if the keywords array contains only alphanumeric characters.