Optimized pick-random-elements-from-list method.

robotgame/logic/lasermirror.py

@@ -33,6 +33,7 @@ import random
 import itertools
 from robotgame.logic.direction import *
 import robotgame.logic.rollingstone as rstone
+import robotgame.misc as misc
 
 class Mirror(object):
     pass
@@ -81,18 +82,16 @@ def generate_simple_playfield(nmirrors):
         succs = (lambda s: lambda d: succ(s(d)))(succs)
         source_direc = succ(source_direc)
 
-    emptys = set(itertools.product(range(12), range(12))) \
-        - set(playfield.keys())
-    emptys = set([(0, y) for y in range(12)]
-                 + [(11, y) for y in range(12)]
-                 + [(x, 0) for x in range(12)]
-                 + [(x, 11) for x in range(12)])
-    for _ in range(nlevers):
-        if not emptys:
-            raise Exception("Not enough space for all levers!")
-        pos = random.choice(list(emptys))
+    emptys = list(
+        set([(0, y) for y in range(12)]
+            + [(11, y) for y in range(12)]
+            + [(x, 0) for x in range(12)]
+            + [(x, 11) for x in range(12)])
+        - set(playfield.keys()))
+    if len(emptys) < nlevers:
+        raise Exception("Not enough space for all levers!")        
+    for pos in misc.pick_random_elements(emptys, nlevers):
         playfield[pos] = Lever
-        emptys.remove(pos)
     return playfield
 
 def _adjust(source_direc, w, h, x, y):