如何在Python中查找列表的当前容量

Python中的 List 主要是动态大小数组的实现（如Java中的 ArrayList 或 C++ 中的向量）。列表的容量是指列表在特定时间可以存储的元素数。当我们将元素附加到列表时，如果大小小于容量，它将存储该元素。如果当前容量超出，则列表调整大小并为将来的插入分配额外空间（有关详细信息，请参阅列表在Python中的工作方式）
查找列表的容量和列表中剩余空间的公式：

这里，
空列表的大小意味着分配给空列表的位数，它因系统而异。
列表中一个块的大小也因系统而异。

列表的长度是指被填充的空间块数

示例 1：

# program to find capacity of the list
  
import sys
l = []
size = sys.getsizeof(l)
print("size of an empty list :", size)
  
# append an element in the list
l.append(1)
  
# calculate total size of the list after appending one element
print("Now total size of a list :", sys.getsizeof(l))
  
# calculate capacity of the list after appending one element
# Considering block size as 8.
capacity = (sys.getsizeof(l)-size)//8
print("capacity of the list is:", capacity)
print("length of the list is :", len(l))
  
# calculate space left the list after appending one element
spaceleft = ((sys.getsizeof(l)-size)-len(l)*8)//8
print("space left in the list is:", spaceleft)

输出

size of an empty list : 64
Now total size of a list : 96
capacity of the list is: 4
length of the list is: 1
space left in the list is: 3

示例 2：

# program to find capacity of the list
import sys
l = []
size = sys.getsizeof(l)
print("size of an empty list :", size)
  
# append four element in the list
l.append(1)
l.append(2)
l.append(3)
l.append(4)
  
# calculate total size of the list after appending four element
print("Now total size of a list :", sys.getsizeof(l))
  
# calculate capacity of the list after appending four element
c = (sys.getsizeof(l)-size)//8
print("capacity of the list is:", c)
print("length of the list is:", len(l))
  
# calculate space left the list after appending four element
spaceleft =((sys.getsizeof(l)-size)-len(l)*8)//8
print("space left in the list is:", spaceleft)

输出

size of an empty list : 64
Now total size of a list : 96
capacity of the list is: 4
length of the list is: 4
space left in the list is: 0

示例 3：

# program to find capacity of the list
import sys
l = []
size = sys.getsizeof(l)
print("size of an empty list :", size)
  
# append five element in the list
l.append(1)
l.append(2)
l.append(3)
l.append(4)
l.append(5)
  
# calculate total size of the list after appending five element
print("Now total size of a list :", sys.getsizeof(l))
  
# calculate capacity of the list after appending five element
c = (sys.getsizeof(l)-size)//8
print("capacity of the list is:", c)
print("length of the list is:", len(l))
  
# calculate space left the list after appending five element
spaceleft =((sys.getsizeof(l)-size)-len(l)*8)//8
print("space left in the list is:", spaceleft)

输出

size of an empty list : 64
Now total size of a list : 128
capacity of the list is: 8
length of the list is: 5
space left in the list is: 3