Issue #20885 has been updated by Dan0042 (Daniel DeLorme). Ah, you mean it doesn't return strictly true/false? That's a good point, although there are precedents like `Numeric#nonzero?` But I'm not so attached to the name "gsub?" itself, it just happened to be the one that made the most sense to me. We could go with anything really. But I'm interested in discussing if this method, under another name, has a place in Ruby core. ---------------------------------------- Feature #20885: String#gsub? https://bugs.ruby-lang.org/issues/20885#change-111067 * Author: Dan0042 (Daniel DeLorme) * Status: Open ---------------------------------------- I would like a variation of sub/gsub that returns a new string if there is a match, or nil otherwise. This can be currently done with `str.dup.gsub!(...)` at the mere cost of 2 unnecessary extra allocations due to String#dup TBH I'm not sure we need yet another gsub method, but what gets me here is that `gsub?` is the primitive operation from which `gsub` and `gsub!` are made. Internally, these two methods work like this: ```ruby def gsub!(...) modified = gsub?(...) and replace(modified) end def gsub(...) gsub?(...) or dup end ``` We can efficiently derive these two methods from `gsub?`, but we cannot efficiently implement `gsub?` in ruby, so it feels regrettable to me that `gsub?` is not available as a built-in. Use cases include: ```ruby # ensure gsub has modified the string newstr = str.gsub?(rx,repl) or raise "str did not contain expected value" # take an action if the string is modified if str = obj.title.gsub?(rx,repl) obj.title = str obj.save end # avoid allocating a new string if there is no change str = str.gsub?(rx,repl) || str ``` -- https://bugs.ruby-lang.org/