1 函数简要
map 函数 | sum 函数 | pow函数 | lambda函数
2 简要计算
2.1 1^2 + 2^2 + 3^2 .....9^2
方法1
print([pow(x,2) for x in range(1,10)]) #[1, 4, 9, 16, 25, 36, 49, 64, 81] print(sum(pow(x,2) for x in range(1,10)))
方法2
print(map(pow,range(1,10),[2 for x in range(9)])) # <map object at 0x7f9c0e4eb6a0> print([i for i in map(pow,range(1,10),[2 for x in range(9)])]) # [1, 4, 9, 16, 25, 36, 49, 64, 81] print(sum(map(pow,range(1,10),[2 for x in range(9)])))
方法3
print(sum(map(lambda x : x ** 2,range(1,10))))
2.2 1^9 + 2^8 + 3^7 .....9^1
方法1
print(sum(map(pow,range(1,10),range(9,0,-1))))
肢解start
print([i for i in range(9,0,-1)]) # [9, 8, 7, 6, 5, 4, 3, 2, 1]
a = map(pow,range(1,10),range(9,0,-1)) print([i for i in a]) [1, 256, 2187, 4096, 3125, 1296, 343, 64, 9]
肢解end
方法2
print([pow(x,y) for x in range(1,10) for y in range(9,0,-1)]) # [1, 1, 1, 1, 1, 1, 1, 1, 1, 512, 256, 128, 64, 32, 16, 8, 4, 2, 19683, 6561, 2187, 729, 243, 81, 27, 9, 3, 262144, 65536, 16384, 4096, 1024, 256, 64, 16, 4, 1953125, 390625, 78125, 15625, 3125, 625, 125, 25, 5, 10077696, 1679616, 279936, 46656, 7776, 1296, 216, 36, 6, 40353607, 5764801, 823543, 117649, 16807, 2401, 343, 49, 7, 134217728, 16777216, 2097152, 262144, 32768, 4096, 512, 64, 8, 387420489, 43046721, 4782969, 531441, 59049, 6561, 729, 81, 9] print(sum([pow(x,y) for x in range(1,10) for y in range(9,0,-1)]))
上面的方法没有达到题目的要求，因为该段代码相对于将两个迭代参数全部遍历计算了一遍
改进为下列代码
print([pow(x,10-x) for x in range(1,10)]) # [1, 256, 2187, 4096, 3125, 1296, 343, 64, 9] print(sum([pow(x,10-x) for x in range(1,10)]))
2.3 12 + 22 + 32 + 42....92
方法1
print([i*10+2 for i in range(1,10)]) # [12, 22, 32, 42, 52, 62, 72, 82, 92] print(sum([i*10+2 for i in range(1,10)]))
方法2
print(sum(map(lambda x : x * 10 + 2,range(1,10))))