Introduction to the set () function and instance parsing in python, pythonset

Introduction to the set () function and instance parsing in python, pythonset

The set function is also one of the python built-in functions, which is a relatively basic function. The detailed introduction and usage are described below.

The set () function creates an unordered, non-repeating element set. It can perform relational tests, delete duplicate data, and compute intersection, difference set, and union.

Set, receives a list as the parameter

List1 = [1, 2, 4] s = set (list1) print (s) # traverse for I in s: print (I) output one by one: set ([1, 2, 3, 4]) 1234

Use add (key) to add elements to the set. duplicate elements are automatically filtered.

List1 = [1, 2, 4] s = set (list1) print (s) s. add (4) s. add (5) print (s) Output: set ([1, 2, 3, 4]) set ([1, 2, 3, 4, 5])

You can use the remove (key) method to delete elements:

List1 = ['A', 'B', 'zhang ', 'Kang'] s = set (list1) print (s) s. remove ('zhang ') print (s) Output: set (['A', 'hang',' B ', 'zhang']) set (['A ', 'hang', 'B'])

Set can also calculate the intersection and union as in Mathematics

List1 = ['A', 'B', 'zhang ', 'hangzhou'] list2 = ['A',' B ', 'C ', 'D'] s1 = set (list1) s2 = set (list2) # intersection, use the & operator s3 = s1 & s2 # Union set, use | Operator s4 = s1 | s2print (s3) print (s4) Output: set (['A', 'B']) set (['A', 'C ', 'B', 'D', 'zhang', 'hangzhou'])

Summary

The above is all about the set () function introduction and instance parsing in python. I hope it will be helpful to you. Interested friends can continue to refer to this site:

《Introduction to functions in the Re module of Python Programming"

《Python Regular Expression re compile function Parsing"

《Parsing the enumerate function code in Python"

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