Question

I would like to create a Ruby pattern to replace all but the last occurrence of a letter.

For example, replace all:

"}" 

with the string:

"} something "

Turn this string:

"{ anything }   { anything } { anything }"

to:

"{ anything } something    { anything } something  { anything }"

EDIT:

What I’ve used so far:

replaceString = "} something"
string.gsub("}", replaceString).reverse.sub(replaceString.reverse, "}").reverse

but I don’t think it is very effective.

Answer 1

You can use positive lookahead:

str = "{ anything }   { anything } { anything }"
pattern = /\}(?=.*\})/
str.gsub(pattern, "} Something")

=> "{ anything } Something   { anything } Something { anything }"