diff --git a/actionpack/lib/action_dispatch/routing/route.rb b/actionpack/lib/action_dispatch/routing/route.rb
index aefebf8f80e0f1b3221163fbe76ab14f59889d63..f91a48e16cb809b69a8881e268a65fe2eae348b4 100644
--- a/actionpack/lib/action_dispatch/routing/route.rb
+++ b/actionpack/lib/action_dispatch/routing/route.rb
@@ -21,11 +21,7 @@ def initialize(set, app, conditions, requirements, defaults, name, anchor)
           conditions[:path_info] = ::Rack::Mount::Strexp.compile(path, requirements, SEPARATORS, anchor)
         end
 
-        @conditions = conditions.inject({}) { |h, (k, v)|
-          h[k] = Rack::Mount::RegexpWithNamedGroups.new(v)
-          h
-        }
-
+        @conditions = Hash[conditions.map { |k,v| [k, Rack::Mount::RegexpWithNamedGroups.new(v)] }]
         @conditions.delete_if{ |k,v| k != :path_info && !valid_condition?(k) }
         @requirements.delete_if{ |k,v| !valid_condition?(k) }
       end
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 7ac07fe4267b76d10856f1cae6fe0d4763b19feb..1a5f21bd09e42809da577c2b11b7b593559f22e4 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -566,13 +566,8 @@ def handle_positional_args(options)
           keys = options.delete(:_positional_keys)
           keys -= options.keys if args.size < keys.size - 1 # take format into account
 
-          args = args.zip(keys).inject({}) do |h, (v, k)|
-            h[k] = v
-            h
-          end
-
           # Tell url_for to skip default_url_options
-          options.merge!(args)
+          options.merge!(Hash[args.zip(keys).map { |v, k| [k, v] }])
         end
 
         def rewrite_authentication(options)