How do I extract a substring from string using a regular expression?

Question

I am new to regular expressions in Ruby.

The string looks something like http://www.site.com/media/pool/product_color_purple.jpg and I am trying to extract from this just the bit which has the colour in it. This can be a variable length, as some of the colours are like prince_purple.jpg.

So I have:

colour = c.attr('src').match(/(.*)color_(.*).jpg/)
puts "Colour is #{colour}"

What colour returns is the string again, instead of the extracted bit, which is the colour. What is going wrong here?

Answer 1

str="http://www.site.com/media/pool/product_color_purple.jpg"
colour = str.match(/color_([^\/.]*).jpg$/)
puts "Colour is #{colour[1]}"

You not get "Colour is purple" because match returns MatchData, not string

Answer 2

url="http://www.site.com/media/pool/product_color_purple.jpg"
color = url.scan(/color_(.*).jpg/)[0][0]
#=> purple

or

url="http://www.site.com/media/pool/product_color_purple.jpg"
color = url.match(/color_(.*).jpg/)[1]
#=> purple