Question

为什么img_list比compressed还要小？

输入

print(sys.getsizeof(img_list[0:1]))
print(img_list[0:1])
print(sys.getsizeof(compressed[0:2]))
print(compressed[0:2])

print(sys.getsizeof(img_list))
print(sys.getsizeof(compressed))

img_arr = np.asanyarray(img)
print(img_arr.shape)

comp_arr = np.asarray(compressed)
print(comp_arr.shape)

输出

72
[[[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [19, 19, 19], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]]
80
[[12, [0, 0, 0]], [1, [19, 19, 19]]]

256
2536

(24, 24, 3)
(306, 2)

Answer 1

sys.getsize()正在欺骗。它返回一个对象的大小；但是，它不考虑该对象属性的大小。换句话说，它不会递归地遍历您要获得大小的对象。最终，您需要自己做：

import sys

l1 = [[[0, 0, 0], [0, 19, 19], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 13, 0], [0, 0, 0], [19, 19, 19], [110, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 12, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]]

l2 = [[12, [0, 0, 0]], [1, [19, 19, 19]]]

def get_size(obj, seen=None):
    """Recursively finds size of objects"""
    size = sys.getsizeof(obj)
    if seen is None:
        seen = set()
    obj_id = id(obj)
    if obj_id in seen:
        return 0
    # Important mark as seen *before* entering recursion to gracefully handle
    # self-referential objects
    seen.add(obj_id)
    if isinstance(obj, dict):
        size += sum([get_size(v, seen) for v in obj.values()])
        size += sum([get_size(k, seen) for k in obj.keys()])
    elif hasattr(obj, '__dict__'):
        size += get_size(obj.__dict__, seen)
    elif hasattr(obj, '__iter__') and not isinstance(obj, (str, bytes, bytearray)):
        size += sum([get_size(i, seen) for i in obj])
    return size
print(get_size(l1))
print(get_size(l2))

输出：

5280
564

参考：Measure the Real Size of Any Python Object

您所做的基本上是：

sys.getsizeof([[]])

和

sys.getsizeof([[], []]) # This is bigger

为什么这个较长的列表比这个较短的列表小？

1 个答案: