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船长杰克

#1 Created at ... [Delete] [Delete and Lock User]

def pi(N):
    #使用itertools模块(感谢@KJT11的答案)
    c = itertools.cycle([4,-4])
    t = itertools.count(1,2)
    return sum(next(c)/next(t) for x in range(N))
    #使用列表生成器
    #return sum([(4 if x%2==0 else -4)/(2*x+1) for x in range(N)])

黛柔时尚女鞋

#2 Created at ... [Delete] [Delete and Lock User]

相当的不错 def pi(N): ' 计算pi的值 '

# step 1: 创建一个奇数序列: 1, 3, 5, 7, 9, ...
n1=itertools.count(1,2) #步进为2
# step 2: 取该序列的前N项: 1, 3, 5, 7, 9, ..., 2*N-1.
n2=itertools.takewhile(lambda x:x<N*2-1,n1)
# step 3: 添加正负符号并用4除: 4/1, -4/3, 4/5, -4/7, 4/9, ...
n3=itertools.cycle([4,-4]) #结合上面的知识,正四负四一直下去
# step 4: 求和:
return sum(next(n3)/next(n1) for x in range(N))

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船长杰克

黛柔时尚女鞋

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Jayce南征北战

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