added Array#-

lib/array.fy

@@ -315,15 +315,32 @@ class Array {
     arr
   }
 
-  def + other_arr {
+  def + other {
     """
-    @return Concatenation of @self with another @Array@
+    @other @Fancy::Enumerable@ to be appended.
+    @return Concatenation of @self with @other.
 
-    Returns concatenation with another @Array@.
+    Returns concatenation with another @Fancy::Enumerable@.
+
+    Example:
           [1,2,3] + [3,4,5] # => [1,2,3,3,4,5]
     """
 
-    clone append: other_arr
+    clone append: other
+  }
+
+  def - other {
+    """
+    @other @Fancy::Enumerable@ to be subtracted from @self.
+    @return @Array@ of elements in @self excluding all elements in @self and @other.
+
+    Returns an @Array@ of all values in @self that are not in @other.
+
+    Example:
+          [1,2,3,4] - [2,4,5] # => [1,3]
+    """
+
+    self reject: |x| { other includes?: x }
   }
 
   def indices {

tests/array.fy

@@ -333,6 +333,14 @@ FancySpec describe: Array with: {
     ([1,2,3,4] + [-1,-2,-3,-4]) is: [1,2,3,4,-1,-2,-3,-4]
   }
 
+  it: "returns all elements not in another collection" with: '- when: {
+    [] - [] is: []
+    [] - [0] is: []
+    [1,2,3,4] - [2,4] is: [1,3]
+    [1,2,3] - [1,2,3,5] is: []
+    ["foo", "bar", "baz"] - ["bar"] is: ["foo", "baz"]
+  }
+
   it: "returns true for all elements" with: 'all?: when: {
     [1,2,3,4] all?: |x| { x < 5 } . is: true
     [1,2,3,4] all?: |x| { x > 0 } . is: true