>>> b = [1, 2, 3, 5, 6, 8 , 5 , 2 , 5]
>>> sub = { 5: 17 }
>>> [sub.get(x, x) for x in b]
[1, 2, 3, 17, 6, 8, 17, 2, 17]

http://python.kr/viewtopic.php?p=77248

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