[Python] set set

1. Definition: A mutable mapping container composed of a series of non - repeating immutable type variables.

Equivalent to a dictionary with only keys and no values ​​(unordered)

2. Basic operations:

• Create a collection

# create empty set
set01 =set()

# create set with default value
set03 = {"a", "b", "c"}

• Add element

# add element
set03.add("efg")
print(set03)

• Delete element

# remove element
set03.remove("a")
print(set03)

• Get all elements

# get all element
for item in set03:
    print(item)

• Collections have deduplication properties, so you can use collections to remove duplicate content.

set02 = set("abcdc")
list01 = list(set02)
str01 = "".join(list01)
print(str01)

3. Mathematical operations

set01 = {1, 2, 3}
set02 = {2, 3, 4}

# 交集 {2, 3}
print(set01 & set02)
# 并集 {1, 2, 3, 4}
print(set01 | set02)
# 补集 {1, 4}
print(set01 ^ set02)
# 子集 True
set03 = {1, 2}
print(set03 < set01)
# 超集 False
print(set03 > set01)