Set-Python3, set set-python3

Source: Internet
Author: User
Tags set set

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'}

 

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.