Python设置discard()函数

discard() 是从集合中删除元素的内置方法。 discard() 方法只接受一个参数。此方法不返回任何值。

句法：

set.discard(element)

如果传递给discard()的元素存在于集合中，则该元素将从集合中移除。即使传递给discard() 方法的元素不存在于集合中，也不会引发异常。

示例 1：丢弃集合中的一个元素

Python3

numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9}
  
print(numbers)
  
# Deleting 5 from the set
numbers.discard(5)
  
# printing the resultant set
print(numbers)

输出：

{1, 2, 3, 4, 5, 6, 7, 8, 9}

{1, 2, 3, 4, 6, 7, 8, 9}

示例 2：丢弃集合中的一个元素

Python3

numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9}
  
print(numbers)
  
# passing an element that is not in set
numbers.discard(13)
# this will not throw any errors but set remains 
# same as before
  
# printing the resultant set
print("\nresultant set : ", numbers)

输出：

{1, 2, 3, 4, 5, 6, 7, 8, 9}

resultant set :  {1, 2, 3, 4, 5, 6, 7, 8, 9}

示例 3 ：丢弃集合中的一个元素

Python3

myset = {'a', 1, "geek", 2, 'b', 'abc', "geeksforgeeks", 8}
  
print(myset)
  
# Deleting a from the set
myset.discard("geek")
  
# printing the resultant set
print(myset)

输出：

{1, 2, ‘b’, ‘a’, 8, ‘geeksforgeeks’, ‘abc’, ‘geek’}

{1, 2, ‘b’, ‘a’, 8, ‘geeksforgeeks’, ‘abc’}

示例 4：丢弃集合中的一个元素

Python3

myset = {'a', 1, "geek", 2, 'b', 'abc', "geeksforgeeks", 8}
  
print(myset)
  
# trying to Delete geeksfrom the set which is not there
myset.discard("geeks")
  
# printing the resultant set
print(myset)

输出：

{1, 2, ‘b’, ‘a’, 8, ‘geeksforgeeks’, ‘abc’, ‘geek’}

{1, 2, ‘b’, ‘a’, 8, ‘geeksforgeeks’, ‘abc’, ‘geek’}