The uniqueness of Sets is that sets are unordered means sets cannot support indexing Python will store the set’s items at random locations and store unique elements means when we try to store duplicate items Python will merge them.
Example
set_a = {"red", "yellow", "orange"}
print(set_a)| Output: {‘red’, ‘yellow’, ‘orange’} |
Access Item
We cannot access items from sets by using index values because as we discussed above sets do not support indexing but we can assess the set’s values by using loops and keywords.
Change Item
After creating a set, we cannot change its items, but we can add new items.
Add one item by using add () method.
Example
set_a = {"red", "yellow", "orange"}
set_a.add("Banana")
print(set_a)| Output: {‘orange’, ‘red’, ‘yellow’, ‘Banana’} |
We add multiple items by using update () method.
Example
set_a = {"red", "yellow", "orange"}
set_a.update(["Pink", "White", "Blue"])
print(set_a)| Output: {‘Blue’, ‘red’, ‘orange’, ‘White’, ‘Pink’, ‘yellow’} |
Print a Set using for Loop
We can also use for loop to print set items in one go except printing one by one.
set_a = {"red", "yellow", "orange"}
for x in set_a:
print(x)| Output: red yellow orange |
Print Length of Set
print number of total Items in the set using len () method:
set_a = {"red", "yellow", "orange"}
for x in set_a:
print(len(x))| Output: 3 6 6 |
Remove item from Set
Use remove () or discard () method to remove an item from set.
Example
Remove “Yellow” by using remove () method:
set_a = {"red", "yellow", "orange"}
set_a.remove("yellow")
print(set_a)| Output: {‘red’, ‘orange’} |
Note: When we try to remove an item which is not exist in the set by using remove () method then, remove () will show an error.
Example
Remove “Yellow” by using discard () method:
set_a = {"red", "yellow", "orange"}
set_a.discard("yellow")
print(set_a)| Output: {‘red’, ‘orange’} |
Note: When we try to remove an item which is not exist in the set by using discard () method then, discard () will show an error.
Pop item from Set
We can use pop () to remove an item from the set pop method removes the last Item from usually and it will return the removed value.
set_a = {"red", "yellow", "orange"}
x = set_a.pop()
print(x)| Output: red |
Note: Sets are unordered so, we have no idea about what item gets removed.
Delete item from Dictionary
The method del () will remove the whole set:
set_a = {"red", "yellow", "orange"}
del set_a # This will delete the set_a variable
print(set_a| Output: Traceback (most recent call last): File “”, line 3, in NameError: name ‘set_a’ is not defined |
Clear items from Set
The clear () method return an empty set:
set_a = {"red", "yellow", "orange"}
set_a.clear()
print(set_a)| Output: set() |
This code clears all elements from the set set_a using the clear() method, resulting in an empty set, which is denoted by {}.
Join Two Sets
In Python there are many methods to join sets.
We can use union () method to join two sets it will return a new set containing all the items from both sets same as we calculate a union of two sets in mathematics.
Example
set1 = {"one", "two", "three"}
set2 = {1, 2, 3}
set3 = set1.union(set2)
print(set3)| Output: {1, 2, 3, ‘two’, ‘three’, ‘one’} |
The update () method will insert all the item of set2 into set1:
Example
set1 = {"one", "two", "three"}
set2 = {1, 2, 3}
set1.update(set2)
print(set1)| Output: {1, 2, 3, ‘three’, ‘two’, ‘one’} |
This code updates set1 by adding all elements from set2 using the update() method. The resulting set set1 contains all unique elements from both set1 and set2.
Create Set by using Constructor
We can also create a Set by using built in constructor Set ():
set_b = set(("red", "yellow", "orange"))
print(set_b)| Output: {‘red’, ‘yellow’, ‘orange’} |
This code creates a set set_b containing the elements “red”, “yellow”, and “orange” using the set constructor, and then prints the set.
Author: TCF Editorial
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