How can I replace words in a string with elements in an array in ruby?

Question

I'm trying to replace words (sequence of characters, more generally) in a string with corresponding values in an array. An example is:

"The dimension of the square is {{width}} and {{length}}" with array [10,20] should give

"The dimension of the square is 10 and 20"

I have tried to use gsub as

substituteValues.each do |sub|
    value.gsub(/\{\{(.*?)\}\}/, sub)
end

But I could not get it to work. I have also thought of using a hash instead of an array as follows:

{"{{width}}"=>10, "{{height}}"=>20}. I feel this might work better but again, I'm not sure how to code it (new to ruby). Any help is appreciated.

Wiktor Stribiżew · Accepted Answer · 2021-10-20 20:55:06Z

2

You can use

h = {"{{width}}"=>10, "{{length}}"=>20}
s = "The dimension of the square is {{width}} and {{length}}"
puts s.gsub(/\{\{(?:width|length)\}\}/, h)
# => The dimension of the square is 10 and 20

See the Ruby demo. Details:

\{\{(?:width|length)\}\} - a regex that matches
- \{\{ - a {{ substring
- (?:width|length) - a non-capturing group that matches width or length words
- \}\} - a }} substring
gsub replaces all occurrences in the string with
h - used as the second argument, allows replacing the found matches that are equal to hash keys with the corresponding hash values.

You may use a bit simpler hash definition without { and } and then use a capturing group in the regex to match length or width. Then you need

h = {"width"=>10, "length"=>20}
s = "The dimension of the square is {{width}} and {{length}}"
puts s.gsub(/\{\{(width|length)\}\}/) { h[Regexp.last_match[1]] }

See this Ruby demo. So, here, (width|length) is used instead of (?:width|length) and only Group 1 is used as the key in h[Regexp.last_match[1]] inside the block.

edited Oct 20, 2021 at 20:55

answered Oct 20, 2021 at 20:12

Wiktor Stribiżew

631k41 gold badges502 silver badges632 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

engineersmnky Over a year ago

More simply gsub can take a hash as a second argument structured as a {match => replacement} e.g. s.gsub(/\{\{(?:width|length)\}\}/,h) #=> "The dimension of the square is 10 and 20"

Collectives™ on Stack Overflow

How can I replace words in a string with elements in an array in ruby?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related