What is a Python list?
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A Python list is an ordered and changeable collection of data objects. Unlike an array, which can contain objects of a single type, a list can contain a mixture of objects.
As evident in the illustration above, a list can contain objects of any data type, including another list. This makes the list data structure one of the most powerful and flexible tools in Pythonic programming.
List creation
Defining a list in Python is really quite simple. The name of the list has to be specified, followed by the values it contains:
# Initiliazing a list with 5 objectsmyList1 = [20, 'Edpresso', [1, 2, 3], 3.142, None]print(myList1)# Initializing an empty listmyList2 = []print(myList2)
Accessing an element
A list element can be accessed using its index. The index is the position of an element in the list.
Similar to other languages, Python list elements are indexed from 0. This means that the first element will be at the 0 index.
To access an element, its index is enclosed in the [] brackets:
myIntList = [1,3,5,2,4]print(myIntList[3]) # Accessing the 4th element
Adding and removing elements
The size of a list is not fixed. Elements can be added and removed at any point.
myList = ['a', 'b', 'c', 'd', 'e', 'f']# Add an element at the endmyList.append('g')print(myList)# Insert element at a specific index# insert(index, value)myList.insert(3, 'z') # Insertion at the 3rd indexprint(myList)# Delete an element from the endmyList.pop()print(myList)# Delete the value at a specific indexdel myList[1]print(myList)# Accessing the length of a listprint(len(myList))
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Ace your System Design Interview and take your career to the next level. Learn to handle the design of applications like Netflix, Quora, Facebook, Uber, and many more in a 45-min interview. Learn the RESHADED framework for architecting web-scale applications by determining requirements, constraints, and assumptions before diving into a step-by-step design process.
