Python 尽管代码完全相同，为什么结果不同？

我想构建一个函数，将两个numpy数组求和为一个新数组，当且仅当不同的索引为euqal时

x = np.array([2,1,1,1])
y=np.array([2,1,0,1])   

overlap = np.zeros(4)
for i in range(0,len(x)):
    if x[i] == y[i]:
        overlap[i]= x[i]+y[i]

print(overlap)
[4. 2. 2. 2.]

这是意料之中的事。现在我想定义函数，但是输出是不同的，尽管代码完全相同

    def sum_overlap(x,y):
       overlap = np.zeros(4)
       for i in range(0,len(x),1):
           if x[i] == y[i]:
              overlap[i] = x[i] + y[i]
              print(overlap)

sum_overlap(x,y)
[4. 0. 0. 0.]
[4. 2. 0. 0.]
[4. 2. 2. 0.]
[4. 2. 2. 2.]

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我认为它与迭代器有关，但我无法理解。

您的print语句处于循环中，因此每次调用它时，它都会打印出列表。将打印语句从循环中取出，但保留在函数中，并且输出应与工作代码相同：

def sum_overlap(x,y):
    overlap = np.zeros(4)
    for i in range(0,len(x),1):
        if x[i] == y[i]:
            overlap[i] = x[i] + y[i]
    return overlap
      

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您打印了多次，但最终结果是相同的。你不应该退回它吗？