def pi(N): ' 计算pi的值 itertools返回的是惰性的iterator ' # step 1: 创建一个奇数序列: 1, 3, 5, 7, 9, ... a = itertools.count(1,2) # step 2: 取该序列的前N项: 1, 3, 5, 7, 9, ..., 2*N-1. aa = itertools.takewhile(lambda x: x <= 2*N - 1, a) # step 3: 添加正负符号并用4除: 4/1, -4/3, 4/5, -4/7, 4/9, ... aaa = list(map(lambda x: 4 / x if x % 4 == 1 else -4 / x, aa)) s = sum(aaa) return s
Sign in to make a reply
Roger_R36