add filter-map

lib/parallel.rb

@@ -304,6 +304,10 @@ def flat_map(*args, &block)
       map(*args, &block).flatten(1)
     end
 
+    def filter_map(*args, &block)
+      map(*args, &block).compact
+    end
+
     # Number of physical processor cores on the current system.
     def physical_processor_count
       @physical_processor_count ||= begin

spec/cases/filter_map.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+require './spec/cases/helper'
+
+result = Parallel.filter_map(['a', 'b', 'c']) do |x|
+  x if x != 'b'
+end
+print result.inspect

spec/parallel_spec.rb

@@ -540,6 +540,12 @@ def cpus
     end
   end
 
+  describe ".filter_map" do
+    it "yields object" do
+      ruby("spec/cases/filter_map.rb 2>&1").should == '["a", "c"]'
+    end
+  end
+
   describe ".any?" do
     it "returns true if any result is truthy" do
       ruby("spec/cases/any_true.rb").split(',').should == ['true'] * 3 * 2