Set-Python3, set set-python3

Set-Python3, set set-python3
The remove () and discard () Methods of set are described.

 

Function/method name

	Equivalent Operator	Description
All set types
Len (s)		Set base: number of elements in set s
Set ([obj])		Variable set factory function: ojb must support iteration. The set is created by elements in obj. Otherwise, an empty set is created.
Frozenset ([obj])		Immutable set factory functions: the execution method is the same as the set () method, but it returns an immutable set.
	Obj in s	Member Testing
	Obj not in s	Non-member test
	S = t	Equivalent test
	S! = T	Non-equivalent test
	S & lt; t	(Strictly) subset Test
S. issubset (t)	S & lt; = t	Subset Test
	S> t	(Strictly) superset Test
S. issuperset (t)	S & gt; = t	Superset Test
S. union (t)	S | t	Merge operations
S. intersec-tion (t)	S & t	Intersection operation
S. difference (t)	S-t	Differential operation
S. symmetric_fifference (t)	S ^ t	Symmetric Difference Operation
S. copy ()		Value assignment operation: returns the (Shortest copy) Copy of s.
Only applicable to variable sets
S. update (t)	S | = t	(Union) Modification Operation: add members in t to s
S. intersection_update (t)	S & = t	Intersection Modification Operation: only contains members of s and t.
S. difference_update (t)	S-= t	Negative Modification Operation: Only Members belonging to s but not t are included in s.
S. symmetric_difference _ update (t)	S ^ = t	Symmetric differential Modification Operation: s contains only s or only t members.
S. add (obj)		Add operation: Add obj to s
S. remove (obj)		Delete operation
S. discard (obj)		Discard operation: remove () a friendly version. If ojb exists in s, delete it from s.
S. pop ()		Pop operation: Remove and return any value in s.
S. clear ()		Clear operation: Remove all elements in s

 

For example:

The following code reports an error because 'l' in row 9th remove () does not exist in the set.

The discard () method does not return an error.

 1 # Code based on Python 3.x 2 # _*_ coding: utf-8 _*_ 3 # __Author: "LEMON" 4  5 names = ['lemon','zw','lr', 'lr'] 6 names_set = set(names) 7  8 names_set.discard('lemo') 9 names_set.remove('l')10 # Error: 'lr' is not in names_set11 print(names_set)

The correct code is as follows:

 1 # Code based on Python 3.x 2 # _*_ coding: utf-8 _*_ 3 # __Author: "LEMON" 4  5 names = ['lemon','zw','lr', 'lr'] 6 names_set = set(names) 7  8 names_set.discard('lemo') 9 names_set.remove('lr')10 # Error: 'lr' is not in names_set11 print(names_set)

 

The running result is as follows:

1 {'lemon', 'zw'}