Create set.py

day4-list_tuples_set_dictionaries/set.py

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+# # Creating a Set
+# # syntax
+# st = {}
+# # or
+# st = set()
+# # syntax
+# st = {'item1', 'item2', 'item3', 'item4'}
+# # eg:
+# fruits = {'banana', 'orange', 'mango', 'lemon'}
+# # Getting Set's Length
+# st = {'item1', 'item2', 'item3', 'item4'}
+# len(st)
+# print(len(st))
+
+# # Checking an Item
+# st = {'item1', 'item2', 'item3', 'item4'}
+# print("Does set st contain item3? ", 'item3' in st) # Does set st contain item3? True
+
+# # Adding Items to a Set
+# fruits = {'banana', 'orange', 'mango', 'lemon'}
+# fruits.add('lime')#添加结果在首位
+# print(fruits)
+
+# # Add multiple items using update()     顺序随机
+# fruits = {'banana', 'orange', 'mango', 'lemon'}
+# vegetables = ('tomato', 'potato', 'cabbage','onion', 'carrot')
+# fruits.update(vegetables)
+# print(fruits)
+# st = {'item1', 'item2', 'item3', 'item4'}
+# st.update(['item5','item6','item7'])
+# print(st)
+
+# # Removing Items from a Set
+st = {'item1', 'item2', 'item3', 'item4'}
+st.remove('item2')
+print(st)
+fruits = {'banana', 'orange', 'mango', 'lemon'}
+fruits.pop()  # removes the last element from the set
+print(fruits)
+
+# Clearing Items in a Set
+fruits = {'banana', 'orange', 'mango', 'lemon'}
+fruits.clear()
+print(fruits) # set()
+
+# Deleting a Set
+# fruits = {'banana', 'orange', 'mango', 'lemon'}
+# del fruits
+# print(fruits)
+
+
+# Converting List to Set
+fruits = ['banana', 'orange', 'mango', 'lemon','orange', 'banana']
+fruits = set(fruits) # {'mango', 'lemon', 'banana', 'orange'}
+print(fruits)
+
+# Joining Sets
+st1 = {'item1', 'item2', 'item3', 'item4'}
+st2 = {'item5', 'item6', 'item7', 'item8'}
+st3 = st1.union(st2)
+
+# Finding Intersection Items
+st1 = {'item1', 'item2', 'item3', 'item4'}
+st2 = {'item3', 'item2'}
+st1.intersection(st2) # {'item3', 'item2'}
+print(st1.intersection(st2))
+
+python = {'p', 'y', 't', 'h', 'o','n'}
+dragon= {'d', 'r', 'a', 'g', 'o','n'}
+print(python.intersection(dragon))     # {'o', 'n'})
+
+# Checking Subset and Super Set
+st1 = {'item1', 'item2', 'item3', 'item4'}
+st2 = {'item2', 'item3'}
+st2.issubset(st1) # True
+st1.issuperset(st2) # True
+
+python = {'p', 'y', 't', 'h', 'o','n'}
+dragon = {'d', 'r', 'a', 'g', 'o','n'}
+python.issubset(dragon)     # Fales
+
+# Checking the Difference Between Two Sets
+# syntax
+st1 = {'item1', 'item2', 'item3', 'item4'}
+st2 = {'item2', 'item3'}
+st2.difference(st1) # set()
+st1.difference(st2) # {'item1', 'item4'} => st1\st2
+
+
+st1 = {'item1', 'item2', 'item3', 'item4'}
+st2 = {'item2', 'item3'}
+st2.difference(st1) # set()
+st1.difference(st2) # {'item1', 'item4'} => st
+
+# Finding Symmetric Difference Between Two Sets
+
+python = {'p', 'y', 't', 'h', 'o','n'}
+dragon = {'d', 'r', 'a', 'g', 'o','n'}
+python.symmetric_difference(dragon)  # {'r', 't', 'p', 'y', 'g', 'a', 'd', 'h'}
+
+
+# Joining Sets
+
+python = {'p', 'y', 't', 'h', 'o','n'}
+dragon = {'d', 'r', 'a', 'g', 'o','n'}
+python.isdisjoint(dragon)  # False, there are common items {'o', 'n'}
+