Some of the challenges people often encounter are when to use the various data types. However, the set as a whole is mutable. It is one of the most core data structures in computer science. If Multiple values are present at the same index position, then the value is appended to that index position, to form a Linked List. You will also learn about frozen sets, which are similar to sets except for one important detail. We can use this property of sets to remove duplicate elements from iterable. Sets are the data types in python that are used to store the collection of data. Set elements are unique. Python also includes a data type for sets. Get a short & sweet Python Trick delivered to your inbox every couple of days. Some are performed by operator, some by method, and some by both. For example, you can’t define a set whose elements are also sets, because set elements must be immutable: If you really feel compelled to define a set of sets (hey, it could happen), you can do it if the elements are frozensets, because they are immutable: Likewise, recall from the previous tutorial on dictionaries that a dictionary key must be immutable. These data can be of any type. The sets in python are typically used for mathematical operations like union, intersection, difference and complement etc. Find unique elements using set. In, Python Sets are implemented using dictionary with dummy variables, where key beings the members set with greater optimizations to the time complexity. 1. add():As the name suggests it used to add a new element in the set. You'll see how to define set objects in Python and discover the operations that they support. It can be an integer, float, string or both. The set doesn’t maintain elements in any particular order. Grouping objects into a set can be useful in programming as well, and Python provides a built-in set type to do so. There are two types of sets in Python: set and frozenset. How to split training and testing data sets in Python? It is an unordered and unique collection of immutable objects. or an iterator object to be converted into a set. However, the set itself is mutable. Common Elements are selected. Python set operation. Two sets can be merged using union() function or | operator. Python Set. The elements in a set can be objects of different types: Don’t forget that set elements must be immutable. Python Set is a programmatic form of sets in mathematics and one of the core data structures in Python. A set contains an unordered collection of unique and immutable objects. Before splitting the data, make sure that the dataset is large enough. The intersection of two sets, say Set A and Set B, can result in a set that contains the elements that are common in both sets, that is, the overlapping part in the diagram below. A set itself may be modified, but the elements contained in the set must be of an immutable type. In python sets are written with curly braces. What is Set? Write a Python program to find the length of a set. Sets are similar to List and Tuples. The function takes either an iterable (like a list or a tuple) or a sequence (lists, tuples, and strings are all sequences). For example, a tuple may be included in a set: But lists and dictionaries are mutable, so they can’t be set elements: The len() function returns the number of elements in a set, and the in and not in operators can be used to test for membership: Many of the operations that can be used for Python’s other composite data types don’t make sense for sets. Maybe you even remember Venn diagrams: If this doesn’t ring a bell, don’t worry! That is 80% of the dataset goes into the training set and 20% of the dataset goes into the testing set. To find difference in between sets. Tuple. Starting with the empty set xx: xx = set([]) # Now we have some other set, for example elements = set([2,3,4]) xx.add In this course, you'll learn how to work with Python's set data type. Curiously, although the ^ operator allows multiple sets, the .symmetric_difference() method doesn’t: Determines whether or not two sets have any elements in common. You'll see how to define set objects in Python and discover the operations that they support. Let us go through the different methods present as built-in Python for Sets. In python sets are written with curly braces. Sets are the data types in python that are used to store the collection of data. 1. If no parameters are passed, it returns an empty frozenset. Note the following about sets: A set is created using the set keyword; A set cannot be an element of a set (but a list can be an element of a list) Also note: As pointed out by Luka Jeličić Lux, Sets cannot have same element multiple times. Values stored in the sets cannot be duplicated. A set in python is a collection of items just like Lists and Tuples. To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. 1. For example, the numbers 2, 4, and 6 are distinct objects when considered separately, but when they are considered collectively they form a single set of size three, written {2,4,6}. Creating Python Sets A set is created by placing all the items (elements) inside curly braces {}, separated by comma, or by using the built-in set () function. Background on sets. The most common split ratio is 80:20. Related Tutorial Categories: To intersect multiple sets, stored in a list l, use the Python one-liner l.pop().intersection(*l) that takes the first set from the list, calls the intersection() method on it, and passes the remaining sets as arguments by unpacking them from the list. Watch it together with the written tutorial to deepen your understanding: Sets in Python. Set is an unordered collection data type with no duplicate elements. Upon completion you will receive a score so you can track your learning progress over time: Python’s built-in set type has the following characteristics: Let’s see what all that means, and how you can work with sets in Python. Python Set. In mathematics, a set is a collection of distinct objects, considered as an object in its own right. If adding an element to a set, and that element is already contained in the set, then the set will not change. That is 80% of the dataset goes into the training set and 20% of the dataset goes into the testing set. The major advantage of using a set, as opposed to a list, is that it has a highly optimized method for checking whether a specific element is contained in the set. This tutorial should still be easily accessible for you. Determine whether one set is a subset of the other. Python set itself is mutable allowing addition and removal of items but the elements are immutable which forbids any change in existing items. Here’s what you’ll learn in this tutorial: You’ll see how to define set objects in Python and discover the operations that they support. Train/Test split works well with large datasets. 4. generate link and share the link here. The most common split ratio is 80:20. What is Set in Python? They are unique. A proper superset is the same as a superset, except that the sets can’t be identical. By using our site, you A set is also considered a superset of itself: Determines whether one set is a proper superset of the other. Duplicate elements are not allowed. In Sets, values are stored inside the curly brackets. Import the entire dataset . But it is in itself mutable by default. Sets are super handy — most frequently being used to eliminate duplicate items in an iterable. While elements of a set can be modified at any time, elements of the frozen set remain the same after creation. Sets are distinguished from other object types by the unique operations that can be performed on them. In mathematics, a rigorous definition of a set can be abstract and difficult to grasp. Join us and get access to hundreds of tutorials, hands-on video courses, and a community of expert Pythonistas: Master Real-World Python SkillsWith Unlimited Access to Real Python. Now, in this tutorial, we will learn how to split a CSV file into Train and Test Data in Python Machine Learning.Moreover, we will learn prerequisites and process for Splitting a dataset into Train data and Test set in Python ML. Leave a comment below and let us know. A Python set is the collection of the unordered items. Compute the intersection of two or more sets. For each, there is a corresponding method as well. Please use ide.geeksforgeeks.org, It means you are increasing the number of elements in the set by one. Like the operations above, there are a mix of operators and methods that can be used to change the contents of a set. Python program to count number of vowels using sets in given string, Output of Python Programs | Set 24 (Sets), Python Set | Pairs of complete strings in two sets, Python program to find common elements in three lists using sets, Python Operators for Sets and Dictionaries, Important differences between Python 2.x and Python 3.x with examples, Python | Set 4 (Dictionary, Keywords in Python), Python | Sort Python Dictionaries by Key or Value, Reading Python File-Like Objects from C | Python. As Set does not allow duplicates, when you convert list to set, all duplicates will be removed in the set. The union of x1 and x2 is {'foo', 'bar', 'baz', 'qux', 'quux'}. You can’t use the built-in set type as a dictionary key: If you find yourself needing to use sets as dictionary keys, you can use frozensets: In this tutorial, you learned how to define set objects in Python, and you became familiar with the functions, operators, and methods that can be used to work with sets. Let us go through the different methods present as built-in Python for Sets. Creating python sets Method-1: Using set() The first method to create a set is to use the in-built set() function. Set elements are unique. Here one very important knowledge about set that needs to be kept in mind is that the element only gets added if it is not already present in the set assets do not take duplicate elements. However, in worst case it can become O(n). Python’s set class represents the mathematical notion of a set. Let’s take a look at how these operators and methods work, using set union as an example. python A set is a unique collection of unordered elements. Below is a list of the set operations available in Python. It is an unordered and unique collection of immutable objects. or collection (set, dictionary, etc.) Share However, set elements are not indexed. In this tutorial, we will learn about set() in detail with the help of examples. basics Python Set Comprehension. But it fits the definition—every element of x is in x. Determines whether one set is a proper subset of the other. In Sets, values are stored inside the curly brackets. If an item is present in more than one set, the result will … No spam ever. Sets are available in Python 2.4 and newer versions. Hence, each element in Python set is unique. The method is invoked on one of the sets, and the other is passed as an argument: The way they are used in the examples above, the operator and method behave identically. The add method also does not return any value. However, there are two major pitfalls in Python sets: Sets and frozen sets support the following operators: Code Snippet to illustrate all Set operations in Python. The objects in curly braces are placed into the set intact, even if they are iterable. Unsubscribe any time. Attention geek! Determine whether one set is a superset of the other. These elements can be on any data types as sets, unlike arrays, are not type specific. But frozensets aren’t. In Python, sets are written with curly brackets. How do you create a set in Python? You can add and delete elements of a set, you can iterate the elements of the set, you can perform standard operations on sets (union, intersection, difference). Home (current) About; More Languages ... Sets are a powerful tool in Python since they have the ability to calculate differences and intersections between other sets. Sets are useful for when dealing with a unique collection of elements – e.g. In the example above, a - b is computed first, resulting in {1, 2, 3, 300}. Python Sets What is a set? To perform intersection, we use ‘&’ operator. What’s your #1 takeaway or favorite thing you learned? Python set operation. This can be done through intersection() or & operator. Python sets have these methods: s.union(t) s | t new set with elements from both s and t s.update(t) s |= t return set s with elements added from t Likewise, there's also these: s.intersection_update(t) s &= t return set s keeping only elements also found in t s.intersection(t) s & t new set with elements common to s and t And so on, for all the standard relational algebra operations. Now in a dictionary, when we have the same keys we can use set to identify the unique keys. Thus, the sets shown above can also be defined like this: Observe the difference between these two set definitions: A set can be empty. A set is yet another mutable sequence type used to store collection of unique items. We can create a set, access it’s elements and carry out these mathematical operations as shown below. This behavior is similar to that of the .append() list method. But it is in itself mutable by default. It may consist of various elements; the order of elements in a set is undefined. 1. add(): As the name suggests it used to add a new element in the set. A set can be created in two ways. You can use python set() function to convert list to set.It is simplest way to convert list to set. Complaints and insults generally won’t make the cut here. They are different from lists or tuples in that they are modeled after sets in mathematics. Set is one of 4 built-in data types in Python used to store collections of data, the other 3 are List, Tuple, and Dictionary, all with different qualities and usage. In this course, you'll learn how to work with Python's set data type. Objective. The set method removes the duplicate elements but the data type is also set. Some objects in Python are modified in place when they are the target of an augmented assignment operator. Strengthen your foundations with the Python Programming Foundation Course and learn the basics. acknowledge that you have read and understood our, GATE CS Original Papers and Official Keys, ISRO CS Original Papers and Official Keys, ISRO CS Syllabus for Scientist/Engineer Exam, G-Fact 19 (Logical and Bitwise Not Operators on Boolean), Difference between == and is operator in Python, Python | Set 3 (Strings, Lists, Tuples, Iterations), Python | Using 2D arrays/lists the right way, Convert Python Nested Lists to Multidimensional NumPy Arrays, Adding new column to existing DataFrame in Pandas, Python program to convert a list to string, How to get column names in Pandas dataframe, Reading and Writing to text files in Python, Creating a Proxy Webserver in Python | Set 2, isupper(), islower(), lower(), upper() in Python and their applications, Python | Program to convert String to a List, Write Interview You should now be comfortable with the basic built-in data types that Python provides. x1.update(x2) and x1 |= x2 add to x1 any elements in x2 that x1 does not already have: x1.intersection_update(x2) and x1 &= x2 update x1, retaining only elements found in both x1 and x2: x1.difference_update(x2) and x1 -= x2 update x1, removing elements found in x2: x1.symmetric_difference_update(x2) and x1 ^= x2 update x1, retaining elements found in either x1 or x2, but not both: Aside from the augmented operators above, Python supports several additional methods that modify sets. A set in Python is a collection of objects. How are you going to put your newfound skills to use? Set objects also support mathematical operations like union, intersection, difference, and symmetric difference. Python’s set class represents the mathematical notion of a set. The intersection operation creates a … x.add() adds , which must be a single immutable object, to x: x.remove() removes from x. Python raises an exception if is not in x: x.discard() also removes from x. learnpython.org is a free interactive Python tutorial for people who want to learn Python, fast. Practically though, a set can be thought of simply as a well-defined collection of distinct objects, typically called elements or members. There are two types of built-in set types: Set Intersection. x1.difference(x2) and x1 - x2 return the set of all elements that are in x1 but not in x2: Another way to think of this is that x1.difference(x2) and x1 - x2 return the set that results when any elements in x2 are removed or subtracted from x1. The difference between the two is that a set is mutable, which means that you can change its contents, while a frozenset is not. x1 > x2 returns True if x1 is a proper superset of x2: A set is not a proper superset of itself: Note: The > operator is the only way to test whether a set is a proper superset. Most, though not quite all, set operations in Python can be performed in two different ways: by operator or by method. The most efficient way to join multiple sets (stored in a list of sets), use the Python one-liner set().union(*list) that creates a new set object, calls the union() method on the new object, and unpacks all sets from the list of sets into the union() method’s argument list. A Python set is an unordered collection of comma separated elements inside curly braces '{ }'. Let us do an example. Set in Python is a data structure equivalent to sets in mathematics. The set data type is, as the name implies, a Python implementation of the sets as they are known from mathematics. brightness_4 A set is simply a collection of items that are unordered. You cannot access items in a set by referring to an index, since sets are unordered the items has no index. Train/Test split works well with large datasets. Set Intersection. Sample Solution:- Python Code: #Create a set seta = set([5, 10, 3, 15, 2, 20]) #Find the length use len() print(len(seta)) Sample Output: 6 Pictorial Presentation: Visualize Python code execution: Email, Watch Now This tutorial has a related video course created by the Real Python team. A common use of sets in Python is computing standard math operations such as union, intersection, difference, and symmetric difference. Creating python sets Method-1: Using set() The first method to create a set is to use the in-built set() function. They are different from lists or tuples in that they are modeled after sets in mathematics. close, link The elements in the set are always unique. set – remove duplicate elements. In most data structures, elements are indexed. Sets can be used to carry out mathematical set operations like union, intersection, difference and symmetric difference. A set is created by using the set() function or placing all the elements within a pair of curly braces. Sets never contain duplicate values. This fails with the | operator but succeeds with the .union() method. Tweet For example, the numbers 2, 4, and 6 are distinct objects when considered separately, but when they are considered collectively they form a single set of size three, written {2,4,6}. Sets in Python are used when-The order of data does not matter ; You do not need any repetitions in the data elements; You need to perform mathematical operations such as union, intersection, etc ; Now let us move ahead and see how to create sets in Python. Enjoy free courses, on us →, by John Sturtz Sets are mutable which means we can modify it after its creation. Python Set Operations. Like a list, a set allows the addition and removal of elements. Note the following about sets: A set is created using the set keyword; A set cannot be an element of a set (but a list can be an element of a list) Also note: As pointed out by Luka Jeličić Lux, Sets cannot have same element multiple times. First, you can define a set with the built-in set() function: In this case, the argument is an iterable—again, for the moment, think list or tuple—that generates the list of objects to be included in the set. Same as checking for an item, i.e., O(1) on average. Sets are mutable (changeable) and do not have repeated copies of elements. x1.issubset(x2) and x1 <= x2 return True if x1 is a subset of x2: A set is considered to be a subset of itself: It seems strange, perhaps. Code: firstset = {"Johnny", "Nilanjan", "… The major advantage of using a set, as opposed to a list, is that it has a highly optimized method for checking whether a specific element is contained in the set. But there is a subtle difference between them. The function takes either an iterable (like a list or a tuple) or a sequence (lists, tuples, and strings are all sequences). A set in python is a collection of items just like Lists and Tuples. Alternately, a set can be defined with curly braces ({}): When a set is defined this way, each becomes a distinct element of the set, even if it is an iterable. x1.issuperset(x2) and x1 >= x2 return True if x1 is a superset of x2: You have already seen that a set is considered a subset of itself. The team members who worked on this tutorial are: Master Real-World Python Skills With Unlimited Access to Real Python. Related course Python Programming Bootcamp: Go from zero to hero. This is based on a data structure known as a hash table. x1.intersection(x2) and x1 & x2 return the set of elements common to both x1 and x2: You can specify multiple sets with the intersection method and operator, just like you can with set union: The resulting set contains only elements that are present in all of the specified sets. Frozen sets in Python are immutable objects that only support methods and operators that produce a result without affecting the frozen set or sets to which they are applied. Compute the difference between two or more sets. Experience, replace “min” with “max” if t is not a set, (n-1)*O(l) where l is max(len(s1),..,len(sn)), the set of elements in precisely one of s1 or s2. We can also use the in-built Python Function named as intersection() to get the same result. Observe the difference between these two statements: Both attempt to compute the union of x1 and the tuple ('baz', 'qux', 'quux'). Set, a term in mathematics for a sequence consisting of distinct language is also extended in its language by Python and can easily be made using set(). While elements of a set can be modified at any time, elements of the frozen set remain the same after creation. Time Complexity of this is O(len(s1) + len(s2)) where s1 and s2 are two sets whose union needs to be done. They are unique. A superset is the reverse of a subset. By the end of this course, you'll have a good feel for when a set is an appropriate choice in your own programs. However, there are a few unique characteristics that define a set and separate it from other data structures: Some operations are performed by operators, some by methods, and some by both. Sets are available in Python 2.4 and newer versions. so we can use the set class to remove duplicate elements from an iterable. I can't figure out how to do it. set() method is used to convert any of the iterable to sequence of iterable elements with distinct elements, commonly called Set. ). It means you are increasing the number of elements in the set by one. As said already, the elements in a set are always unique. Next, you will begin to explore how the code that operates on those objects is organized and structured in a Python program. It can be an integer, float, string or both. One of my favorite data types in Python is the set. In Python, set union can be performed with the | operator: Set union can also be obtained with the .union() method. See your article appearing on the GeeksforGeeks main page and help other Geeks. finding the unique elements within a list to determine if there are are any values which should be present. edit A proper subset is the same as a subset, except that the sets can’t be identical. Creating a set. The set items are also unindexed. Python set itself is mutable allowing addition and removal of items but the elements are immutable which forbids any change in existing items. By the end of this course, you'll have a good feel for when a set is an appropriate choice in your own programs. The principle outlined above generally applies: where a set is expected, methods will typically accept any iterable as an argument, but operators require actual sets as operands. This article is contributed by Jay Patel. There is no corresponding method. The .union() method, on the other hand, will take any iterable as an argument, convert it to a set, and then perform the union. Tuple is one of 4 built-in data types in Python used to store collections of data, the other 3 are List, Set, and Dictionary, all with different qualities and usage.. A tuple is a collection which is ordered and … They are similar to iteration over the Hash lists and combining the same values on both the Table. In set theory, a set x1 is considered a subset of another set x2 if every element of x1 is in x2. But observe: Python does not perform augmented assignments on frozensets in place. Sets are mutable and iterable (more on these properties later). Sets. In this class, you’ll discover – what is a Python set and what are its properties. Note: Notice that the element 'baz', which appears in both x1 and x2, appears only once in the union. Take the Quiz: Test your knowledge with our interactive “Python Sets” quiz. If x is empty, x.pop() raises an exception: Python provides another built-in type called a frozenset, which is in all respects exactly like a set, except that a frozenset is immutable. Sets in Python The data type "set", which is a collection type, has been part of Python since version 2.4. In Python, a set is a data structure that stores unordered items. In other words, we can add and remove items in a set. A set x1 is considered a superset of another set x2 if x1 contains every element of x2. A Set is an unordered collection data type that is iterable, mutable and has no duplicate elements. There are no duplicate elements in a set and you can add or even delete items in it. The intersection of two sets, say Set A and Set B, can result in a set that contains the elements that are common in both sets, that is, the overlapping part in the diagram below. This is done through difference() or – operator. Sets in Python A set in Python is a collection of objects. Perhaps you recall learning about sets and set theory at some point in your mathematical education. Let’s see what all that means, and how you can work with sets in Python. But you can loop through the set items using a for loop, or ask if a specified value is present in a set, by using the in keyword. Writing code in comment? A set is a collection that is unordered and unindexed. John is an avid Pythonista and a member of the Real Python tutorial team. Each element in the set must be unique, immutable, and the sets remove the duplicate elements. The mathematical definition of sets is the same as the definition of sets in Python. The key perspective of set comprehension that makes it different is that it returns a set, which means the items inside the set will be unordered and cannot contain duplicates. Stuck at home? It can have any number of items and they may be of different types (integer, float, tuple, string etc. Set: Set can be defined as a collection of elements where all elements are unique. Time complexity of finding difference s1 – s2 is O(len(s1)). Once again, you can specify more than two sets: When multiple sets are specified, the operation is performed from left to right. There is no corresponding method. Only instances of immutable types can be added to a Python set. A set x1 is considered a proper superset of another set x2 if x1 contains every element of x2, and x1 and x2 are not equal. Creating Sets If we want to create a set, we can call the built-in set function with a sequence or another iterable object. A set itself may be modified, but the elements contained in the set must be of an immutable type. code. Duplicate elements are not allowed. You can still use in to check for membership of a given item. basics Then c is subtracted from that set, leaving {1, 2, 3}: Compute the symmetric difference between sets. A set x1 is considered a proper subset of another set x2 if every element of x1 is in x2, and x1 and x2 are not equal. A set is a unique collection of unordered elements. x1.symmetric_difference(x2) and x1 ^ x2 return the set of all elements in either x1 or x2, but not both: The ^ operator also allows more than two sets: As with the difference operator, when multiple sets are specified, the operation is performed from left to right. Given two sets, x1 and x2, the union of x1 and x2 is a set consisting of all elements in either set. Since a frozenset is immutable, you might think it can’t be the target of an augmented assignment operator. This explains, why sets unlike lists or tuples can't have multiple occurrences of the same element. And removal of elements of data Python program to find the length a! A set set: set can be used to store the collection of distinct objects typically. Or collection ( set, then the set data type is, as the implies. Set doesn ’ t be indexed or sliced dataset is large enough theory at some point your... Carry out mathematical set operations in Python and discover the operations above, there is a of... Quality standards can have any number of elements convert list to determine if there are no elements. Class, you might think it can ’ t allow multiple occurrences of the same keys we can it! Learn these methods later etc. subset, except that the element 'baz ', 'bar,... Function or placing all the elements within a pair of curly braces the... The various data types in Python over the hash lists and combining the same result '', is... From mathematics duplicates, when you convert list to set.It is simplest way to convert list determine! Goes into the testing set colons ) team of developers so that it meets our high quality standards are handy. Discussed data Preprocessing, Analysis & Visualization in Python in to check for membership a. If you find anything incorrect, or you want to create a in! 2.4 and newer versions simply a collection that is unordered and unique collection of immutable.... But observe: Python does not perform augmented assignments on frozensets in place for x in name_of_set:.... Placed into the training set and 20 % of the iterable to sequence of iterable elements with distinct elements commonly! This fails with the.union ( ) in detail with the written tutorial to deepen understanding. A team of developers so that it meets our high quality standards above! Structured in a set can be abstract and difficult to grasp an object. Elements are unique iterable to sequence of iterable elements with distinct elements, commonly called set or. At any time, elements of the unordered items difference and symmetric difference between sets such as,! If they are iterable operations above, there is no literal for an empty set Python. Using curly braces ' { } ' ' } ( n ) from the iterable! Class represents the mathematical notion of a collection of unique and immutable objects union of x1 and x2, elements... And that element is unique, iterable and immutable objects if adding element... S built-in set type to do it adding an element to a new in. That stores unordered items items and they may be of immutable type, sets themselves be. Another set x2 if x1 contains every element of x is in x. Determines whether one set is a of! As set does not return any value single variable ' } the duplicate elements but elements! Another set x2 if x1 contains every element is unique, immutable, and symmetric.... Difference s1 – s2 is O ( len ( s1 ) ) in either set record value is to! Use in to check for membership of a set is a data structure that stores items... When you convert list to determine if there are are sets in python values which should present! A new element in Python is created by a team of developers so that it meets high! Topic discussed above { 1, 2, 3 }: Compute the symmetric difference your mathematical.... The length of a set elements of a set by referring to an,. Function or | operator but succeeds with the Python DS course, unlike arrays, not... Of itself: Determines whether one set is an unordered collection of and... T worry elements inside curly braces are placed into the training set 20! Increasing the number of items just like lists and combining the same values on both table... Meets our high quality standards be useful in programming as well, and the sets can be. Defined for mathematical operations like union, intersection, difference and symmetric difference anything incorrect, or.! Can become O ( 1 ) on average those objects is organized and structured in a set contains unordered. Be modified ) like to contribute, you 'll learn how to define set objects that generally mimic operations., since sets are useful for when dealing with a sequence ( string, tuple, string both... Or you want to create a set can be an integer, float, tuple, or. Elements or members, even if they are different from list in the set type. Set class to remove duplicate elements ', which appears in both and! Of different types ( integer, float, tuple, string or both n't have multiple occurrences the! Or sliced placing all the elements in any particular order set type to do so common use of sets the. Bell, don ’ t modifying the original x: Test your knowledge our! Just like a list in { 1, 2, 3, }. Object x originally referenced is gone iteration over the hash table foundations with the written tutorial to deepen your:... ( len ( s1 ) ) optional ) - a sequence ( string tuple!