Question

I have a hash like:

{:name => 'foo', :country => 'bar', :age => 22}

I also have a string like

Hello ##name##, you are from ##country## and your age is ##age##. I like ##country## 

Using above hash, I want to parse this string and substitute the tags with corresponding values. So after parsing, the string will look like:

Hello foo, you are from bar and your age is 22. I like bar

Do you recommend taking help of regex to parse it? In that case if I have 5 values in the hash, then I would have to traverse through string 5 times and each time parsing one tag. I don’t think that is a good solution. Is there any better solution?

Answer 1

Here is my solution to the problem:

h = {:name => 'foo', :country => 'bar', :age => 22}
s = "Hello ##name##, you are from ##country## and your age is ##age##. I like ##country##}"
s.gsub!(/##([a-zA-Z]*)##/) {|not_needed| h[$1.to_sym]}

It generally makes a single pass using regex and does the replacement I think you need.