diff --git a/README.md b/README.md
index d831881..ad39d19 100644
--- a/README.md
+++ b/README.md
@@ -80,12 +80,6 @@ calls to `fn` return true.
 lume.all({1, 2, 1}, function(x) return x == 1 end) -- Returns true
 ```
 
-### lume.set(t)
-Returns a copy of the array `t` with all the duplicate values removed.
-```lua
-lume.set({2, 1, 2, "cat", "cat"}) -- Returns {1, 2, cat}
-```
-
 ### lume.reduce(t, fn [, first])
 Applies `fn` on two arguments cumulative to the items of the array `t`, from
 left to right, so as to reduce the array to a single value. If the `first`
@@ -94,6 +88,13 @@ argument is not supplied the accumulator is initialised to `0`.
 lume.reduce({1, 2, 3}, function(a, b) return a + b end) -- Returns 6
 ```
 
+### lume.set(t, [, isarray])
+Returns a copy of the `t` table with all the duplicate values removed. If
+`isarray` is true the table is treated as an array.
+```lua
+lume.set({2, 1, 2, "cat", "cat"}) -- Returns {1, 2, cat}
+```
+
 ### lume.filter(t, fn [, isarray])
 Iterates the table `t` and calls `fn` on each value. Returns a new table with
 only the value which `fn` returned true. If `isarray` is true the table is
diff --git a/lume.lua b/lume.lua
index 9255c4e..ccf4f02 100644
--- a/lume.lua
+++ b/lume.lua
@@ -102,15 +102,6 @@ function lume.any(t, fn)
 end
 
 
-function lume.set(t)
-  local tmp = {}
-  for k, v in pairs(t) do tmp[v] = k end
-  local rtn = {}
-  for k, _ in pairs(tmp) do rtn[#rtn + 1] = k end
-  return rtn
-end
-
-
 function lume.reduce(t, fn, first)
   local acc = first
   if acc == nil then acc = 0 end
@@ -119,6 +110,17 @@ function lume.reduce(t, fn, first)
 end
 
 
+function lume.set(t, isarray)
+  local tmp = {}
+  for k, v in pairs(t) do tmp[v] = k end
+  local rtn = {}
+  for k, v in pairs(tmp) do 
+    rtn[isarray and (#rtn + 1) or v] = k
+  end
+  return rtn
+end
+
+
 function lume.filter(t, fn, isarray)
   local rtn = {}
   for k, v in pairs(t) do