Set

• unordered
• unchangeable(cannot change the items after the set has been created)
• unindexed
• do not allow duplicate

Note

Set items are unchangeable, but you can remove items and add new items.

thisset = {"apple", "banana", "cherry"}

len()

Set Items

set1 = {"apple", "banana", "cherry"}
set2 = {1, 5, 7, 9, 3}
set3 = {True, False, False}
set4 = {"abc", 34, True, 40, "male"}

type()

< class 'set'>

constructor

thisset = set(("apple", "banana", "cherry")) # note the double round-brackets
print(thisset)

Access Items

value in thisset

Adding

add()

thisset = {"apple", "banana", "cherry"}
thisset.add("orange")

Add items from another set

thisset = {"apple", "banana", "cherry"}
tropical = {"pineapple", "mango", "papaya"}

thisset.update(tropical)

Note

update() method does not have to be a set, it can be any iterable object (tuples, lists, dictionaries etc.)

Removing

1. remove()

thisset = {"apple", "banana", "cherry"}
thisset.remove("banana")
print(thisset)

Note

If the item to remove does not exist, remove() will raise an error.

2. discard()

thisset.discard("banana")

Note

If the item to remove does not exist, discard() will NOT raise an error.

3. pop() - del last
4. clear() - empties the set

thisset = {"apple", "banana", "cherry"}
thisset.clear()
print(thisset)

5. del - delete the set completely

del thisset

Join Two Sets

both will exclude any duplicate items.

1. union - ret. new set

set1 = {"a", "b" , "c"}
set2 = {1, 2, 3}

set3 = set1.union(set2)
print(set3)

2. update

set1 = {"a", "b" , "c"}
set2 = {1, 2, 3}

set1.update(set2)
print(set1)

Keep ONLY the Duplicates

1. intersection_update() - present in both

x = {"apple", "banana", "cherry"}
y = {"google", "microsoft", "apple"}

x.intersection_update(y)

print(x)

2. intersection() - new set, present in both

Keep All, But NOT the Duplicates

1. symmetric_difference_update() - are NOT present in both
2. symmetric_difference() - a new set, NOT present in both

Set Methods

Set methods