九、字典推导
Python不光列表用推导式，字典/集合也有
#列表
l=[[0 for i in range(4)] for i in range(4)]#生成二维列表
print(l)
# [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]]
testDict = {i: i * i for i in xrange(10)}
testSet = {i * 2 for i in xrange(10)}
print(testSet)
print(testDict)
#set([0, 2, 4, 6, 8, 10, 12, 14, 16, 18])
#{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36, 7: 49, 8: 64, 9: 81}
