Ruby multiple string replacement
Since Ruby 1.9.2, String#gsub
accepts hash as a second parameter for replacement with matched keys. You can use a regular expression to match the substring that needs to be replaced and pass hash for values to be replaced.
Like this:
'hello'.gsub(/[eo]/, 'e' => 3, 'o' => '*') #=> "h3ll*"
'(0) 123-123.123'.gsub(/[()-,. ]/, '') #=> "0123123123"
In Ruby 1.8.7, you would achieve the same with a block:
dict = { 'e' => 3, 'o' => '*' }
'hello'.gsub /[eo]/ do |match|
dict[match.to_s]
end #=> "h3ll*"
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.
You could do something like this:
replacements = [ ["☺", ":)"], ["☹", ":("] ]
replacements.each {|replacement| str.gsub!(replacement[0], replacement[1])}
There may be a more efficient solution, but this at least makes the code a bit cleaner
Late to the party but if you wanted to replace certain chars with one, you could use a regex
string_to_replace.gsub(/_|,| /, '-')
In this example, gsub is replacing underscores(_), commas (,) or ( ) with a dash (-)