In this article you will learn about Python List.
Python List – List is a Python in-built function and it contains four type of data types.
The data types are following as –
1. List – It is ordered collection and contains changeable elements. It also allows duplicate elements (repetition of elements).
2. Tuple – It is ordered collection and contains unchangeable elements. It also allows duplicate elements (repetition of elements).
3. Set – It is collection of unordered and unindexed elements. It doesn’t allow duplicate elements.
4. Dictionary – It is unordered collection and contains unindexed elements. It doesn’t allow duplicate elements.
Let’s begin with first Python List –
List – It is ordered collection and contains changeable elements. In Python list are defined with square brackets [].
Example 1- Creation of a list.
x = ['Hello', 'Python', 'world'] print(x)
Access elements – In Python, list elements can get using index number of elements.
Index number – In Python, Index number starts from 1.
| H | E | L | L | O |
| 1 | 2 | 3 | 4 | 5 |
Example 2- Get the element of position 2.
x = ['Hello', 'Python', 'world'] print(x[2])
Note: – In beginning index number starts from 0.
Negative indexing – It defined as indexed number of elements from end starting with -1 for last first element and -2 for last second element and so on.
| H | E | L | L | O |
| -5 | -4 | -3 | -2 | -1 |
Example 3- Get the element of position 3 from end.
x = ['Hello', 'Python', 'world']
print("Element of position 3 from end is:" , x[-3])
Note: In ending index number starts from -1.
Range of indexes – It specified range of index number to get particular element from start to end.
Specifying range returns new list of specified elements.
Example 4- Get particular elements from index number 1 to 2.
x = ['Welcome', 'in', 'programming', 'language']
print("Element from index number 1 to 3 is:" , x[1:3])
Note: Starting index number (1) is included but ending number (3) is excluded.
Example 5- Start search from beginning to till particular element.
x = ['Welcome', 'in', 'programming', 'language'] print(x[:3])
Example 6- Start search from any elements or mid to get elements till end.
x = ['Welcome', 'in', 'programming', 'language'] print(x[1:])
Range of Negative Indexes – Start search from end to get particular elements from start to end.
Example 7- Start search from end and get particular elements from start to end.
x = ['Welcome', 'in', 'programming', 'language'] print(x[-4:-1])
Negative indexing – It defined as indexed number of elements from end starting with -1
Change Item Value – It defined as change of particular elements by describing index number of changeable elements.
Example 8- Change element ‘language’ into ‘Python’.
x = ['Welcome', 'in', 'programming', 'language'] x[2] = 'Python' print(x)
Now we are going to learn some important functions of list.
Loop in list – It is possible to loop though list by using ‘for’ loop.
Example 9- Use of ‘for’ loop to looping through list.
z = ['Welcome', 'in', 'programming', 'language']
for x in z:
print(x)
Note: We will learn more about ‘for’ loop later in detail.
Check element exits – To check particular element exits, use ‘in’ keyword.
Example 10- Check if element ‘programming’ exits.
x = ['Welcome', 'in', 'programming', 'language']
print('programming' in x)
Length of list – To get length of list use ‘len’ function.
Example 11- Use len() function to get length.
x = ['Welcome', 'in', 'programming', 'language'] print(len(x))
Add element – To add an element at the end position of list, use append() function.
Example 12- Use of append() method to add element at the end position.
x = ['Welcome', 'in', 'Python']
print('before adding:' , x)
x.append('language')
print('After adding:' , x)
To add an element at the specified index number, use insert() method.
x = ['Python', 'Java', 'HTML'] x.insert(2, 'JavaScript') print(x)
Remove elements – To remove any elements from list, use remove() method. There are so many other functions too to remove elements. They are follows as ‘pop()’, ‘del’ and clear.
Example 13- Use of remove() method to remove any element.
x = ['Python', 'Java', 'HTML']
x.remove('Java')
print(x)
pop() method – By default it removes last element.
Example 14- Use of pop() method to remove last element.
x = ['Python', 'Java', 'HTML']
print("before removing:" , x)
x.pop()
print("After removing:" , x)
del() method – If index number is specified it deleted that particular indexed number element, otherwise delete whole list.
Example 15- Use of del() method to delete particular element.
x = ['Python', 'Java', 'HTML']
print('before deleting:' , x)
del x[1]
print("after deleting", x)
Example 16- Use of del method to delete whole list.
x = ['Python', 'Java', 'HTML']
print('before deleting:' , x)
del x print("after deleting" , x)
clear() method – It left an empty list.
Example 17- Use of clear() method to empty list.
x = ['Python', 'Java', 'HTML']
print("before clearing:" , x)
x.clear()
print("after clearing:" , x)
Copy list – To copy a list Python has two function-
copy() method – It is used to copy a list.
list() method – It is used to copy a list.
Example 18- Use of copy() method to copy a list.
x = ['Python', 'Java', 'HTML'] z = x.copy() print(x)
Example 19- Use of list() method to copy a list.
x = ['Python', 'Java', 'HTML'] z = list(x) print(z)
Join list – In Python, list can be easily joined or concatenated by using + operator.
Example 20- Concatenation of two lists.
x = [1,2,3] z = [4,5,6] print(x+z)
Example 21- Joining two lists by appending one list elements to another list one by one.
x = [1,2,3]
z = [4,5,6]
for c in z:
x.append(c)
print("after appending:" , x)
extend() method – It adds element of one list into the another list.
x = [1,2,3] z = [4,5,6] x.extend(z) print(x)
The list() Constructor – It uses to construct or make new list.
Example 22- Use of constructor to make new list.
x = list((1,2,3,4,5)) print(x)
If you find anything incorrect in above discussed topic and have any further question, please comment down below.
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