Ruby multiple string replacement

Question

str = \"Hello☺ World☹\"

Expected output is:

\"Hello:) World:(\"

I can do this: str.gsub(\"☺\", \":)\").gsu

Answer 1

Set up a mapping table:

map = {'☺' => ':)', '☹' => ':(' }

Then build a regex:

re = Regexp.new(map.keys.map { |x| Regexp.escape(x) }.join('|'))

And finally, gsub:

s = str.gsub(re, map)

If you're stuck in 1.8 land, then:

s = str.gsub(re) { |m| map[m] }

You need the Regexp.escape in there in case anything you want to replace has a special meaning within a regex. Or, thanks to steenslag, you could use:

re = Regexp.union(map.keys)

and the quoting will be take care of for you.