How To Use Sets in Python

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Sets are a collection of unique elements which have the same value. They can be used in many different programming languages, so it’s important to know how they work and how you use them.

The “set in python example” is a set that contains the numbers from zero to nine. It can be used in Python as follows:

How To Use Sets in Python

Study how to utilize sets in Python as a starting place for Python programmers and learners to learn and/or code on more sophisticated topics such as Lambda functions, Map Reduce, Java Collections API, and Python collections interface.

This lesson will go through various common applications of the set data structure in the Python programming language, along with examples to help you grasp the ideas.

Continue reading to get started!

Prerequisites

This will be a hands-on presentation in this course. If you want to follow along, make sure you have the following items on hand:

  • Installed Python v3 or later environment.
  • VS Coding is a code editor that can execute Python code.

How Do You Install Python 3.6? Related:How Do You Install Python 3.6?

Making Your First Python Sets

Lists, which are ordered collections of changeable data, and dictionaries, which store data in key-value pairs, are two data structures in Python. The term “mutable” refers to data that can be modified after it has been created. Sets have features in common with both lists and dictionaries. Sets are modifiable collections of single items, similar to lists.

Because sets are not a sequence, they lack an index, making them more analogous to dictionaries, which are also unordered collections. Python speeds up look-up operations by significantly optimizing sets and dictionaries.

In a dictionary, you can search up a key to acquire a value, such as discovering someone’s name and then looking up their phone number in an address book. Sets, on the other hand, do not include key-value pairs. Instead, you verify whether an element exists in a set by looking it up inside the set. Membership testing is the term for this notion.

It’s time to make a set to learn! A set is created by adding components to it. Let’s get your hands a little grubby!

1. In the terminal, open an interactive Python session.

2. Create a set by executing the set() function and passing in any kind of data you wish to add once your Python session is ready. To construct your first set, copy and paste the code below into your Python session and hit Enter. With the set literal: curly brackets, you’re defining the my firs set variable. The first and only element is the ATA, Hello World string.

‘ATA, Hello World’ is the first set in my first set.

3. Check that your first set is created by running the command below.

In reply, you’ll receive the string ATA, Hello World, as seen below.

Making a set and naming it Making a set and naming it

4. You can double-check that my first set is a set by getting the data type of my first set using the type() method. To find out what data type you have, run the code below.

You’ll obtain the following result. My first set is a set, according to the output.

Checking the type of my first setChecking the type of my first set

5. Because a set is a collection, it has a length function: len (). To find out how long the set is, use the code below.

Because the set only has one element, you’ll receive 1 in response, as seen below. A singleton set is defined as a set with precisely one element.

determining the set's length determining the set’s length

Defining Properties of Sets Understanding

A set has two defining qualities, which you’ll learn about next. Nobody hates spoilers, so continue reading to learn about these qualities and begin coding.

Copy and paste the code below into a new file called set comparison.py.

# You’ll build a few different sets. The first set includes the numbers 1, 2, 3, while the second set has the numbers 3, 2, 1 in a different sequence. # To compare the sets, use the double equal symbol ==. # You’ll also utilize a print statement to publish the outcome of this comparison. print(1, 2, 3 == 3, 2, 1); print(1, 2, 3 == 3, 2, 1); print(1, 2, 3 == 3, 2, 1); print(1, 2, 3 =

To execute the set comparison.py script and report the comparison output, type the command below in your IDE.

As an output, you’ll receive true, as seen below: Python compared the two sets and determined that they were equal. They’re both the same length and include the same components.

When an element is part of a set, it must be distinct from other elements. A set is a mathematical object that maintains track of all the unique values in a particular collection or string.

1 Python sets are not sequences; the order of the set’s components is irrelevant. Sets are not in any particular sequence.

Comparing sets and noting that the order of the items is irrelevant Comparing sets and noting that the order of the items is irrelevant

After that, you’ll discover how sets deal with duplicate values. Copy and paste the code below into a new file called set integer number.py. Each member of this set literal will be an integer, separated by commas, with some numbers repeating in any sequence.

1 2 3 4 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4

To print members of the set, use the command below.

set integer number.py in Python

You’ll obtain an output similar to the one below, indicating that set integer number only includes the unique numbers 1, 2, 3, and 4. Despite the fact that you’ve spoken practically all of them before. There are only four members in the set when Python evaluates, constructs, and prints it out.

When an element is part of a set, it must be distinct from other elements. A set is a mathematical object that maintains track of all the unique values in a particular collection or string.

2 There is no duplicate data in Python sets: there are no duplicate values. Members vary from one another in a number of ways.

The code tries to duplicate values in a set, yet there are no duplicate values in sets. The code tries to duplicate values in a set, yet there are no duplicate values in sets.

By utilizing the len() function to print out the length of this set, you may double-check whether duplicate values are saved. Remove the preceding text from the set integer number.py file and replace it with the line below.

print(len(1, 2, 3, 2, 3, 4, 3, 4, 4, 4, 4)) print(len(1, 2, 3, 2, 3, 4, 3, 4, 4, 4, 4) print(len(1, 2, 3, 2, 3,

To get the length of the set, use the command below.

set integer number.py in Python

The number 4 will appear in the output, indicating that there are only four members in the collection.

The number 4 will appear in the output, as illustrated.The number 4 will appear in the output, as illustrated.

Compare and contrast these features with a real-life set example. Apples, bananas, oranges, lemons, and limes are a group of fruits. It makes no difference what sequence the fruits are in. Nothing will change if the list is rearranged in a different order. The list of fruits is still the same. Apples aren’t as valuable as bananas or lemons.

All of the fruits are one-of-a-kind and distinct from one another. You wouldn’t say bananas five times if someone asked you to list five fruits: one is plenty. Bananas are already in the set, so adding them again won’t make a difference.

Adding Elements to a Python Set is a simple process.

You learnt how to build a new Python set in the previous section. You’ll learn how to handle Python sets in this section. The first step is to add items to a set.

Sets in Python are changeable, which means that the data inside them may be altered after they’ve been created.

When it comes to adding items to a set, there are two options. The add() function creates a single element, while the update() method creates several elements.

Create a new file called set vowels.py and put the following code into it.

# You’ll create a new variable vowels and give it an empty set of values. set of vowels () #To add one element to the set, use the add() function. # Now we’ll add A, the initial vowel. vowels. add(‘A’) #Print the new set that includes the new element. print(vowels)

To make sure you’re adding components to the set, run the code below.

You’ll receive something like this as a result. When you print set vowels content, you’ll see that it displays ‘A,’ indicating that ‘A’ is a member of set vowels.

Printing the whole set Printing the whole set

Instead of adding the remaining vowels one by one, use the update technique to combine them all at once.

In your set vowels.py file, copy and paste the line below. The iterable type, which is a string, will be used: U, E, O, and I. The update function will iterate over each element, making the string iterable, and adding each element to the set one by one.

updateVowels(‘U, E, O, I’)

Check that the collection includes all four freshly added vowels by running the code below.

You’ll obtain the following result. As you can see, it completes the set with all of the vowels.

Examining the collection Examining the collection

For these string data types, the order is non-deterministic. So it’s alright if your vowels come out in a different sequence; it’s operating as it should.

Getting Rid of Elements in a Python Set

You learnt how to add items to a set in the previous section. You’ll learn how to delete components from a set in this section.

To delete an element from a Python set, you may use one of four methods:

Let’s take a look at each strategy individually. The vowels from the previous section will be used in the instances. To avoid affecting the original set, you’ll make a replica of it instead.

The set is copied using the copy() function. To create a copy for each deleting technique, copy and paste the lines below into your set vowels.py file.

vowels = clear method remove method = vowels; copy(); remove method = vowels; remove method = vowels; remove discard method = vowels; copy(); copy(); copy(); copy(); copy(); copy(); clear method = vowels.copy() copy() clear method = vowels.copy() copy() clear method = vow ()

The Clear Method should be learned.

The first method is clear(), which has the syntax set.clear (). There is no rationale for this technique.

To call out the clear() function and print out the clear method set, copy and paste the lines below into your set vowels.py file.

print(clear method) clear method.clear()

If you run the code below, you’ll receive an empty set like the one below. The clear() function erased all of the set’s items.

Creating a blank deck of cards Creating a blank deck of cards

Using the Method to Remove

Now we’ll look at the delete() function. The element you wish to delete from the set is the only parameter for this function. set.remove is the syntax for the remove() method (element). This method will be used in the code that follows.

remove method = vowels is a method for removing vowels from a string. remove method. copy() # Rmove the letter A. remove(‘A’) print(remove method)

Check if the letter A was removed from the remove method set by running the code below.

You’ll receive something like this as a result. As you can see, A is no longer included in the collection.

A is no longer included in the collection.A is no longer included in the collection.

You’ll receive a key error if you attempt to delete an element that doesn’t exist in the set. Let’s use the delete() function with the B letter, which isn’t a part of the set.

remove method = vowels is a method for removing vowels from a string. copy() remove method.remove(‘B’) print(remove method)

If you rerun set vowels.py, you’ll receive an error message like the one below.

Getting an error message Getting an error message

Using the Discard Method to Remove Elements

The discard() function is the third method. The element you wish to delete from a set is the only input for this function.

The distinction between remove() and discard() is that the discard() function does not throw an error if an element does not exist. This function prevents a KeyError from being raised, and you may use discard() as many times as you like.

set.discard is the syntax for the discard() method (element). Copy and paste the code below once more. Python will not produce an error this time since you will reject the B letter, which is not a member of the set.

vowels = vowels = vowels = vowels = vowels = vowels = vowels = copy() discard method. discard(‘B’) print(discard method)

See what happens if you run set vowels.py again.

You’ll obtain a result similar to the one below. There is no mistake, as you can see.

There are no errors when an element is discarded that is not part of the set. There are no errors when an element is discarded that is not part of the set.

Using the Pop Method to Remove Elements

The pop() function is the final one. This function accepts no arguments and returns the deleted element after removing a random element from the set. set.pop is the syntax for the pop() method ().

To use the pop() function and print out the deleted element, copy and paste the code below.

Vowels = pop method pop method = copy() vowel print(vowel) print(pop method) pop()

When you run set vowels.py, you’ll see an output similar to the one below. There are five vowels in the initial vowel set. The method removes and returns the vowel O from your pop method set, which contains four vowels.

Using pop to remove a random piece () Using pop to remove a random piece ()

You could have obtained a different result since pop() removes a random piece. If you run the code many times, you’ll observe the randomization at work.

To verify the randomness of pop(), run the script again. To verify the randomness of pop(), run the script again.

Conclusion

You should now have a better understanding of Python sets and the methodology needed to create, remove or add elements to sets. As a next step, why not explore set operations & sets vs. lists?

Python Input: Accepting User Input into Python Scripts is a related topic.

The “python sets contains” is a mathematical set. Sets are used in Python to store collections of objects and can be used to find out if an object is part of the set, or whether it exists in the whole collection. Reference: python set contains.

Frequently Asked Questions

How do sets work in Python?

How do you apply a set in Python?

A: In Python, the set type is an unordered mathematical collection of distinct objects. The easiest way to think about it is as a list of unique values with no duplication. You can create sets using the built-in set() function or by iterating over your own lists and building up sets manually. For example, you could use this syntax in Python 2.7:

What is set in Python with example?

A: a = 1
b = 2
c = 3

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