myset = {“apple”, “banana”, “cherry”}
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.
Example
Create a Set:
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.
Output:
{‘cherry’, ‘apple’, ‘banana’}
Note: Sets are unordered, so you cannot be sure in which order the items will appear.
Set Items
Set items are unordered, unchangeable, and do not allow duplicate values.
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.
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)
Output:
{‘banana’, ‘cherry’, ‘apple’}
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))
Output:
3
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}
Output:
{‘cherry’, ‘apple’, ‘banana’}
{1, 3, 5, 7, 9}
{False, True}
A set can contain different data types:
Example
A set with strings, integers and boolean values:
set1 = {“abc”, 34, True, 40, “male”}
Output:
{True, 34, 40, ‘male’, ‘abc’}
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))
Output:
<class ‘set’>
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”)) # note the double round-brackets
print(thisset)
#Note: the set list is unordered, so the result will display the items in a random order.
Output:
{‘cherry’, ‘banana’, ‘apple’}