Python Lists, Creating Lists, Accessing Values in Lists, Updating Lists, Delete List Elements, and Built-in List Functions and Methods.
Python Lists
The sequence is the most basic data structure in Python, Each element of a sequence is assigned a number – its position or index. The first index is zero, the second index is one, and so forth.
Python has six built-in types of sequences, but the most common ones are Lists and Tuples.
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The list is the most versatile datatype available in Python which can be written as a list of comma-separated values (items) between square brackets. The important thing about a list is that items in a list need not be of the same type.
Example:
list1 = [10, 20, 30, 40, 50]
list2 =[19.23, 20.45, 5.678, 9.86]
list3 = [“Java”, “Python”, “JavaScript”, “VBScript”]
list4= [True, False, False, None]
list5 =[“Python”, “Java”, 10, 10.234, True]
Print Lists
print (list1)
print (list2)
print (list3)
print (list4)
print (list5)
Print a List line by Line
list1 =[“Python”, “Java”, 10, 10.234, True]
print(list1)
print(“”)
for i in list1:
print (i)
1. Accessing Values in Lists
To access values in lists, use the square brackets for slicing along with the index.
Examples:
abc = [“Selenium”, “UFT”, “SilkTest”, 100, 200, 300]
print (abc)
print (abc[1])
2. Updating Lists
You can update single or multiple elements of lists by giving the slice on the left-hand side of the assignment operator, and you can add elements in a list with the append() method.
Example:
list = [‘physics’, ‘chemistry’, 1997, 2000]
print (list)
print (list[2])
list[2] = 9999
print (list);
print (list[2])
3. Delete List Elements
To remove a list element, you can use either the del statement if you know exactly which element(s) you are deleting or the remove() method if you do not know.
Example:
list1 = [‘physics’, ‘chemistry’, 1997, 2000]
print (list1)
del (list1[2])
print (list1)
4. Built-in List Functions & Methods / Operations on Python Lists
i. len()
Gives the total length of the list.
Example:
list = [10, 20, 30, 40, 50]
print (len(list))
ii. max()
Returns item from the list with max value.
Example:
list = [10, 20, 30, 40, 50]
print (max(list))
iii. min()
Returns item from the list with min value.
Example:
list = [10, 20, 30, 40, 50]
print (min(list))
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Methods with Description
i. append() method
Appends object obj to list
Example:
list = [10, 20, 30, 40, 50]
print(list)
list.append(70)
print(list)
ii. remove() method
Removes an element from a list by element value.
Example:
list = [10, 20, 30, 40, 50]
print(list)
list.remove(50)
print(list)
iii) reverse() method
Reverses elements of list in place
Example:
list = [10, 20, 30, 40, 50]
print(list)
list.reverse()
print(list)
Python Step by Step Tutorial
1. Introduction to Python Programming Language
2. Download and Install Python
Python Environment Setup (Using PyCharm IDE)
4. Python Keywords and Identifiers
9. Python Conditional Statements
11. Python Branching Statements
14. Python Data Structures – Lists
15. Python Data Structures – Sets
16. Python Data Structures – Tuples
17. Python Data Structures – Dictionaries
18. Python User Defined Functions
25. Python Regular Expressions
26. Python Object-Oriented Programming
29. Abstraction and Encapsulation in Python