Perfect numbers: Difference between revisions

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@@ Line 2,143: / Line 2,143: @@
 Or, a little faster (by restricting the search space):
-<lang python>from functools import (reduce)
+<lang python>from operator import (add)
-from operator import (add)
 from math import (sqrt)
@@ Line 2,152: / Line 2,151: @@
-# perfect:: Int - > Bool
+# perfect::Int - > Bool
 def perfect(n):
     lows = filter(
@@ Line 2,158: / Line 2,157: @@
         xrange(1, 1 + int(sqrt(n)))
     )
-    return (1 < n) and (n == reduce(
+    return (1 < n) and(
-        add,
+        n == sum(
-        lows + concatMap(
+            lows + concatMap(
-            lambda x: (
+                lambda x: (
-                lambda y=n / x: [y] if x != y else []
+                    lambda y=n / x: [y]
-            )()
+                    if x != y
-        )(lows), 0) / 2)
+                    else []
+                )()
+            )(lows)
+        ) / 2
+    )
-# GENERIC -----------------------------------------
+# GENERIC-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -
-# concatMap :: (a -> [b]) -> [a] -> [b]
+# concatMap::(a - > [b]) - > [a] - > [b]
 def concatMap(f):
     return lambda xs: (