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📜  Python Set.pop()方法

📅  最后修改于: 2020-10-30 06:04:46             🧑  作者: Mango

Python Set pop()方法

Python pop()方法从集合中弹出一个元素。它不带任何参数，但返回弹出的元素。如果该元素不存在于集合中，则会引发错误。请参见示例，下面给出了该方法的签名。

函数接口

pop()

传入参数

没有参数。

返回

它返回已删除的元素，或者如果集合为空则抛出错误。

我们来看一些pop()方法的示例，以了解其功能。

Python Set pop()方法示例1

一个使用pop()方法的简单示例，该方法删除一个元素并修改该集合。

# Python set pop() Method
# Creating a set
set = {1,2,3,4,5}
# Displaying elements
print(set) 
# Calling function
el = set.pop()
print("Element popped:",el)
print("Remaining elements: ",set)
el = set.pop()
print("Element popped:",el)
print("Remaining elements: ",set)
el = set.pop()
print("Element popped:",el)
print("Remaining elements: ",set)
el = set.pop()
print("Element popped:",el)
print("Remaining elements: ",set)

输出：

{1, 2, 3, 4, 5}
Element popped: 1
Remaining elements:  {2, 3, 4, 5}
Element popped: 2
Remaining elements:  {3, 4, 5}
Element popped: 3
Remaining elements:  {4, 5}
Element popped: 4
Remaining elements:  {5}

Python Set pop()方法示例2

如果集合为空，则会向调用者函数抛出错误KeyError。参见示例。

# Python set pop() Method
# Creating a set
set = {1,2}
# Displaying elements
print(set) 
# Calling function
el = set.pop()
print("Element popped:",el)
print("Remaining elements: ",set)
el = set.pop()
print("Element popped:",el)
print("Remaining elements: ",set)
el = set.pop()
print("Element popped:",el)
print("Remaining elements: ",set)

输出：

{1, 2}
Element popped: 1
Remaining elements:  {2}
Element popped: 2
Remaining elements:  set()
Traceback (most recent call last):
  File "main.py", line 13, in 
    el = set.pop()
KeyError: 'pop from an empty set'

Python Set pop()方法示例3

此示例按顺序包含添加和弹出元素以描述其功能。

# Python set pop() Method
# Creating a set
set = {1,2}
# Displaying elements
print(set) 
# Calling function
el = set.pop()
print("Element popped:",el)
print("Remaining elements: ",set)
set.add(4)
el = set.pop()
print("Element popped:",el)
print("Remaining elements: ",set)
set.add(5)
el = set.pop()
print("Element popped:",el)
print("Remaining elements: ",set)

输出：

{1, 2}
Element popped: 1
Remaining elements:  {2}
Element popped: 2
Remaining elements:  {4}
Element popped: 4
Remaining elements:  {5}