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what is list in python with example :

Welcome everyone, today we are going to learn what is list in python?Before going to learn if you want to learn python for free then click on python tutorials point.The most Important thing about a lists is that items of in list not need always be the same data type.

In this post, we will discuss python is in list.

Definition of Python list :

A list is a data type in which you to store various types data. remember List is a compound data types in python.

In a list we can be use integer, float items i.e.different-two data types under a lists.

In Python the most basic data structures is the sequence. Each elements of a sequence is assigned its positions or index. The first index in python is zero, the second index is increment by one, and so on.

Python also has six built-in type of sequences like as lists and tuples.

There are different operation include indexing,multiplying, slicing, and checking ,adding.

Python is in Lists :

How to create list in python ?

Creating a lists is very simple by putting different comma-separated value between square bracket.

For example −

list1 = [‘python’, ‘matlab’, 2015, 2020];

list2 = [5, 6, 7, 8, 9 ];

list3 = [“p”, “q”, “r”, “s”]

Some Basic List Operation:

fig 01)what is list in python with example-Method/index in list

Python Expression	Results	Description
len([1, 2, 3,4])	4	Length
[1, 2, 3] + [4, 5, 6] +[7,8,9]	[1, 2, 3, 4, 5, 6,7,8,9]	Concatenation
[‘pythonslearning!’] * 2	[‘pythonslearning!’, ‘pythonslearning’]	Repetition
3 in [1, 2, 3]	True	Membership
for x in [pythonslearning, 2, 3]: print x,	pythonslearning 2 3	Iteration

1. Create a List in Python

In the previous section we see How to create list in Python. Creating a lists is very simple by putting different comma-separated value between square bracket.

# list of floats

num_list = [11.22, 9.9, 68.34, 15.0]

# list of int, float and strings

mix_list = [1.13, 7, 5, “pythonslearning”, 100, “love”]

# an empty list

nodata_list = []

List can have data items of different types or same types . Hence lists comes under compound data types.

2. Accessing the items from a list

Syntax to access the list items:

list_name[index]

Example:

# a list of numbers

numbers = [24, 26, 28, 35, 40, 50]

# prints 24

print(numbers[0])

# prints 35

print(numbers[3])

# prints 50

print(numbers[5])

Output:

Points to Note:

1. The index cannot be a float number.

For example:

# a list of numbers

numbers = [10, 25, 30, 35, 40, 50]

# error

print(numbers[3.0])

Output:

TypeErrors: list indices always be integers not float

# a list of numbers

numbers = [11, 22, 33, 100, 200, 300]

# error

print(numbers[6])

Output:

IndexError: list index out of range

python list index :

3. Negative Index to access the list items from the end :

Python allow you to use negative indexes in different ways:

3.1 Example of Negative indexes in Python

# a list of strings

my_list = [“python”, “Matlab”, “java”, “Arduino”]

# prints “python”print(my_list[-1])

# prints “Matlab”print(my_list[-2])

# prints “Arduino”print(my_list[-3])

Output:

Matlab
Java
Arduino

4. How to get a sublist in Python using slicing

Using the slicing operation we can get a sub list from a lists in Python.

4.1 Slicing example

# numbers in list

number_list = [96, 97, 98, 99, 100]

# list items from 2nd to 3rd

print(number_list[1:3])

# lists item from beginning to third

print(number_list[:3])

# list items from fourth to end of lists

print(number_list[3:])

# Whole list

print(number_list[:])

Output:

[97,98]
[96,97,98]
[97,98,99,100]
[[96,97,98,99,100]

5. List Operations

THERE ARE DIFFERENT TYPES OF OPERATION IN LIST OF PYTHON

We can see one by one

1. Addition

2. Update Element

3. Delete element

5.1 Addition

From the different method you can add element to a lists.

# numbers is in list

number_list = [96, 97, 98, 99]

# At the 4th location adding element 404

number_list.insert(3, 404)

# list: [96, 97, 98, 404, 99]

print(number_list)

# Adding element at the end of the listS 505

number_list.append(505)

# list: [96, 97, 98, 404, 99, 505]

Output:
[96, 97, 98, 404, 99]
[96, 97, 98, 404, 99, 505]

5.2 Update elements

we can see on the bases of example:

# numbers in list

n_list = [96, 97, 98, 99]

# Changing the value of 2rd item

n_list[1] = 101

# list: [96, 101, 98, 99]print(n_list)

# Changing the values of 1st to 3rd items

n_list[0:3] = [12, 13, 14]

# list: [12, 13, 14, 99]

print(n_list)

Output:
[96, 101, 98, 99]
[12, 13, 14, 99]

5.3 Delete elements

# list of numbers

number_list = [11, 23, 33, 46, 51, 68]

# Deleting 3nd element

del number_list[2]

# list: [11, 23, 46, 51, 68]print(number_list)

# Deleting elements from 2nd to 4th

del number_list[1:4]

# list: [11, 68]

print(number_list)

# Deleting the all list

del number_list

Output:
[11, 23, 46, 51, 68]
[11, 68]

Python List Method :

Method	Description
append()	This method Add an elements at the end of the lists
clear()	This method Remove all the element from the lists
copy()	This method Return a copy of the lists
count()	This method Return the numbers of element with the specified value
extend()	This method Add the element of a list to the end of the current lists
index()	This method Return the index of the first elements with the specified value
insert()	This method Add an elements at the specified positions
pop()	This method Remove the elements at the specified positions
remove()	This method Remove the first item with the specified value
reverse()	This method Reverse the order of the lists
sort()	This method Sort the lists

Tags: What is a list in Python?,What are the list methods in Python?,How do you write a list in Python?,python is in lists,Accessing the items from a list,python list index

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