(40) Python Sets

type()

From Python's perspective, sets are defined as objects with the data type 'set': <class 'set'> Example What is the data type of a set? myset = {"apple", "banana", "cherry"} print(type(myset))

Set Items

Set items are unordered, unchangeable, and do not allow duplicate values.

Set Items - Data Types

Set items can be of any data type: Example String, int and boolean data types: set1 = {"apple", "banana", "cherry"} set2 = {1, 5, 7, 9, 3} set3 = {True, False, False} print(set1) print(set2) print(set3) A set can contain different data types: Example A set with strings, integers and boolean values: set1 = {"abc", 34, True, 40, "male"} print(set1)

Unchangeable

Sets are unchangeable, meaning that we cannot change the items after the set has been created. Once a set is created, you cannot change its items, but you can add new items.

Duplicates Not Allowed

Sets cannot have two items with the same value. Example Duplicate values will be ignored: thisset = {"apple", "banana", "cherry", "apple"} print(thisset)

Python Collections (Arrays)

There are four collection data types in the Python programming language: List is a collection which is ordered and changeable. Allows duplicate members. Tuple is a collection which is ordered and unchangeable. Allows duplicate members. Set is a collection which is unordered and unindexed. No duplicate members. Dictionary is a collection which is unordered and changeable. No duplicate members. When choosing a collection type, it is useful to understand the properties of that type. Choosing the right type for a particular data set could mean retention of meaning, and, it could mean an increase in efficiency or security.

The set() Constructor

It is also possible to use the set() constructor to make a set. Example Using the set() constructor to make a set: thisset = set(("apple", "banana", "cherry")) print(thisset) # Note: the set list is unordered, so the result will display the items in a random order.

Set

Sets are used to store multiple items in a single variable. 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. A set is a collection which is both unordered and unindexed. Sets are written with curly brackets. thisset = {"apple", "banana", "cherry"} print(thisset) # Note: the set list is unordered, meaning: the items will appear in a random order. # Refresh this page to see the change in the result. Note: Sets are unordered, so you cannot be sure in which order the items will appear.

Get the Length of a Set

To determine how many items a set has, use the len() method. Example Get the number of items in a set: thisset = {"apple", "banana", "cherry"} print(len(thisset))

Unordered

Unordered means that the items in a set do not have a defined order. Set items can appear in a different order every time you use them, and cannot be referred to by index or key.