Python 3.9 Sets and Sets Function Example

Python 3.9 Sets and Sets Function Example

In this post, you’ll learn sets in Python. And how to create, adding or removing elements from sets in python. We will take examples with python in-built functions on sets.

Sets in python

The set list created in Python is very simple. You will learn everything about Python sets here. In order to understand the end better, we also have many examples with Python sets and with in-built Python methods.

What is a set in Python?

In Python programming, a set is an unordered item collection list. And every item in this list is unique. Also, this list is immutable. The sets are defined by having values between curly brackets { }.

The meaning of immutable is that the list cannot change the item.

However, the sets itself is mutable. We can add or remove items from it.

Python create sets

We have explained about lists, and tuple in back python tutorials. These are different from both Python sets. Now we will know how to create sets in Python.

Let’s take an example. In which we will create a python sets:

mysets = {1, 2, 3, 4}
print(mysets)

Output

{1, 2, 3, 4}

Access sets in python

So far we have learned how to make sets in Python. But now we will know how to access the sets in Python.

To access the sets in Python we can use the for a loop.

Now, we will create a new set and access it with the help of for loop:

mysets = {1, 2, 3, 4}
for a in mysets:
  print(a)

Output

 1
 2
 3
 4

Python change sets

As we already mentioned python sets are immutable. So once you have created the Python sets, you cannot change its items. But it can add and remove items.

Python in-built methods

Now we will tell you about some Python in-built methods that you can use with Python sets.

You can do add, update, remove, etc. to Python sets with these methods.

Add item to set python

Let us now show you how to add a single item in Python sets.

To add a single item to the Python sets, we use the Python add () method. This method adds a single item/element to the Python sets.

You can see its example below:

mysets = {1, 2, 3, 4}

mysets.add(5)

print(mysets)

Output

{1, 2, 3, 4, 5}

Add multiple items to set python

Let us now show you how to add a multiple items in Python sets.

To add multiple items to the Python sets, we use the Python update() method. This method adds a multiple item/element to the Python sets.

You can see its example below:

mysets = {1, 2, 3, 4}

mysets.update([5, 6, 7])

print(mysets)

Output

{1, 2, 3, 4, 5, 6, 7}

Find length of set in python

If you have any sets and want to remove their length. So you have to use the len () function of Python.

Python’s len() function also finds the length of sets, lists, tuples, etc.

Python: Find the length of a set example:

mysets = {1, 2, 3, 4}

mysets.update([5, 6, 7])

print(len(mysets))


Output

7

Remove item from set python

Python has many methods to remove items from sets such as remove (), discard () method etc. By using these Python built-in methods, items from Python sets can be removed.

There is a method in which an error throws if the item is not found in the sets list. And a method in which there is no error throw if the item is not found in Python sets.

Remove item from set python using remove()

mysets = {1, 2, 3, 4}

mysets.remove(2)

print(mysets)

Output

{1, 3, 4}

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

Remove item from set python using discard()

mysets = {1, 2, 3, 4}

mysets.discard(2)

print(mysets)

Output

{1, 3, 4}

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

Python Set Methods

We have given a list of built-in python methods below. There are many methods on this list. Which you can use with Python sets.

The built-in Python methods are given in this list. Some of these methods have examples with Python sets above.

MethodDescription
add()Adds an element to the set
clear()Removes all the elements from the set
copy()Returns a copy of the set
difference()Returns a set containing the difference between two or more sets
difference_update()Removes the items in this set that are also included in another, specified set
discard()Remove the specified item
intersection()Returns a set, that is the intersection of two other sets
intersection_update()Removes the items in this set that are not present in other, specified set(s)
isdisjoint()Returns whether two sets have a intersection or not
issubset()Returns whether another set contains this set or not
issuperset()Returns whether this set contains another set or not
pop()Removes an element from the set
remove()Removes the specified element
symmetric_difference()Returns a set with the symmetric differences of two sets
symmetric_difference_update()inserts the symmetric differences from this set and another
union()Return a set containing the union of sets
update()Update the set with the union of this set and others

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