Python Tutorials
Python Introduction
Python Get Started
Python Syntax
Python Comments
Python Variables
Python Data Types
Python Casting
Python Strings
Python Booleans
Python Operators
Python Lists
Python Tuples
Python Sets
Python Dictionaries
Python If...Else
Python While Loops
Python For Loops
Python Functions
Python Lambda
Python Arrays
Python Classes/Objects
Python Inheritance
Python Iterators
Python Scope
Python Modules
Python Dates
Python Math
Python JSON
Python RegEx
Python PIP
Python Try..Except
Python User Input
Python String Formatting
Python File Handling
Python File Handling
Python Read Files
Python Create/Write Files
Python Delete Files
Python Modules
Python Numpy
Python Pandas
Python SciPy
Previous
Python Sets
myset = {"apple", "banana", "cherry"}
Set
Sets are used to store multiple items in one place.
Set is one of 4 data types built into Python that are used to store data collections, the other 3 List, Tuple, and a dictionary, all with different attributes and uses.
Set a random, unmodified *, and unidentified collection.
*Note: Default items do not change, but you can delete items and add new items.
Sets are written in italics.
Example
Create a Set:
thisset = {"apple", "banana", "cherry"}
print(thisset)
Note: The sets are not in order, so you cannot be sure which system will appear.
Set Items
The set items are random, unchanged, and do not allow duplicate values.
Unordered
Non-order means that items in the set do not have a specified order.
Default items may appear in a different format each time you use them, and cannot be referenced by index or key.
Unchangeable
The preset items do not change, which means we will not be able to change the items once they have been created.
Once a set has been created, you can't change its elements, but you can remove items and add new ones.
Duplicates Not Allowed
Sets cannot have two items of the same value.
Example
Duplicate values will be ignored:
thisset = {"apple", "banana", "cherry", "apple"}
print(thisset)
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))
Set Items - Data Types
Set items can be any type of data:
Example
String, int and boolean data types:
set1 = {"apple", "banana", "cherry"}
set2 = {1, 5, 7, 9, 3}
set3 = {True, False, False}
The set may contain different types of data:
Example
A set with strings, integers and boolean values:
set1 = {"abc", 34, True, 40, "male"}
type()
From Python's point of view, sets are defined as data sets:
<class 'set'>
Example
What is the data type of a set?
myset = {"apple", "banana", "cherry"}
print(type(myset))
The set() Cosntructor
It is also possible to use the set() to create the set.
Example
Using the set() constructor to make a set:
thisset = set(("apple", "banana", "cherry")) # note the double round-brackets
print(thisset)
Python Collections (Arrays)
There are four types of data collection in Python editing language:
- The list is a ordered and flexible collection. Allows duplicate members.
- Tuple is a ordered and unchanged collection. Allows duplicate members.
- Set is a random, unstable *, and unidentified collection. No duplicate members.
- The dictionary is a ordered order ** and is flexible. No duplicate members.
* Set items do not change, but you can delete items and add new items.
** Starting with version 3.7 of Python, dictionaries are in order. In Python 3.6 and earlier, dictionaries are not organized.
When choosing a type of collection, it is helpful to understand the characteristics of that type. Choosing the right type of specific data set may mean keeping the definition, and, it may mean increased efficiency or security.
Python - Access Set Items
Access Items
You can not access the set items by pointing to the index or key.
But you can enter the settings using a loop, or ask if the specified value is in the set, by using the key in.
Example
Loop through the set, and print the values:
thisset = {"apple", "banana", "cherry"}
for x in thisset:
print(x)
Example
Check if "banana" is present in the set:
thisset = {"apple", "banana", "cherry"}
print("banana"
in thisset)
Change Items
Once a set has been created, you can not change its elements, but you can add new items.