class FixedSizeHeap: def __init__(self, max_size): self.max_size = max_size self.heap = [] def push(self, item): if len(self.heap) < self.max_size: heapq.heappush(self.heap, item) else: min_item = heapq.heappop(self.heap) if item > min_item: heapq.heappush(self.heap, item) else: heapq.heappush(self.heap, min_item) def pop(self): return heapq.heappop(self.heap) def __len__(self): return len(self.heap)对于这样的类怎么打印类中的元素

要打印类中的元素，可以通过实现`__str__`方法来实现。`__str__`方法应该返回一个字符串，该字符串包含对象的信息。例如，以下代码演示了如何在类中实现`__str__`方法以打印堆的元素：

import heapq

class FixedSizeHeap:
    def __init__(self, max_size):
        self.max_size = max_size
        self.heap = []
        
    def push(self, item):
        if len(self.heap) < self.max_size:
            heapq.heappush(self.heap, item)
        else:
            min_item = heapq.heappop(self.heap)
            if item > min_item:
                heapq.heappush(self.heap, item)
            else:
                heapq.heappush(self.heap, min_item)

    def pop(self):
        return heapq.heappop(self.heap)

    def __len__(self):
        return len(self.heap)
    
    def __str__(self):
        return str(self.heap)

new_heap = FixedSizeHeap(5)
new_heap.push(1)
new_heap.push(2)
new_heap.push(3)
new_heap.push(4)
new_heap.push(5)
print(new_heap)  # 输出 [1, 2, 3, 4, 5]

在这个例子中，我们定义了`__str__`方法来返回堆的元素。我们将`self.heap`转换为字符串并返回。现在，当我们打印`new_heap`时，它将打印堆中的元素。