Python Basic introduction （ A full set of nanny level tutorials ）

Chapter two

Section 12 ：set aggregate

set aggregate , set Sets are unordered
Do not hash : python Medium set When a collection stores data . You need to hash the data , Store data according to the calculated hash value set The set requires that the stored data must be hashable . Variable data types , list, dict, set
Can hash : Immutable data types , int, str, tuple, bool.

s = {
    1," Ha ha Da ",2,3}
print(type(s))
print(s)

# Here is set Only hashable ones can be placed in it .
s = {
    1, 2, 3, " ha-ha ", (1, 2, 3), []}  # unhashable type: 'list'
print(s)

add increase

s = set()  #  Create an empty set 

s.add(" Zhao Benshan ")
s.add(" Fan Wei ")
s.add(" Gentiana ")
print(s)

remove Delete
Want to modify . Delete first . Add new
for loop , Used for query

s.remove(" Gentiana ")
s.add(" Shen Tang ")
print(s)

for item in s:
    print(item)

summary ：
set aggregate , set Sets are unordered
add increase
remove Delete
for loop , Used for query
The key is to understand hash
Do not hash : python Medium set When a collection stores data . You need to hash the data , Store data according to the calculated hash value set The set requires that the stored data must be hashable . Variable data types , list, dict, set
Can hash : Immutable data types , int, str, tuple, bool.