Notes
<div style='text-align:center'>List Methods
Lists have many built-in methods that are quite useful **
Append Method
This adds an element at the end of list.
lst=[1,2,3,4]
lst.append(5)
#lst has now become [1,2,3,4,5]
Clear Method
This method is used to remove all elements of a list.
lst=[1,2,3,4]
lst.clear()
#lst is now equal to []
Copy Method
If we want to make a copy of a list , then we can do this by the following way:-
lst=[1,2,3,4]
lst_copy=lst
But a disadvantage of making a copy of list by this way is that if we modify lst_copy ,then lst also get changed automatically because lst_copy actually points to lst.
So in order to make a true copy of any list , the following method is used:-
lst=[1,2,3,4]
lst_copy=lst.copy()
#Now lst_copy has become the true copy of lst
Count Method
Suppose if our list has elements that have been repeated multiple times and we want to count the number of times an element has been repeated , then following method helps us in doing so:-
lst=[1,1,1,3,4,2,6,6,4,1]
count=lst.count(1)#Parameter inside is the element that we want to count
#Printing count would give us an output 4 which is the number of times 1 has been repeated in lst
Extend Method
Now if we want to add elements of any list or iterable to a particular list , then use the following method:-
lst=[1,2,3,4]
add_this=[5,6,7,8]
lst.extend(add_this)
#Now lst has become [1,2,3,4,5,6,7,8]
Index Method
If we ever want to know the index of first occurrence of any element of a list ,then use the following method:-
lst=[1,2,3,4,1]
index=lst.index(1)
#The value of index has now become equal to 0
Insert Method
If we ever want to add a specific element to a list in a specified position , then use the following method:-
lst=[1,2,4,5]
lst.insert(2,3)#First parameter is the index where element has to be inserted while the second parameter is the element to be inserted.
Pop Method
If we want to remove an element from a specified index , then use the following method:-
lst=[1,2,3,3,4]
lst.pop(2)#Parameter inside is the index of element to be removed
#lst is now [1,2,3,4]
Remove Method
If we ever want to remove the first occurrence of any element of a list , then use the following method:-
lst=[1,2,3,3,4]
lst.remove(3)#Parameter inside is the element whose first occurrence is to be removed
#lst is now [1,2,3,4]
Reverse Method
If we ever want to reverse any list , then use the following method:-
lst=[1,2,3,4]
lst.reverse()
#lst is now [4,3,2,1]
Sort Method
If we ever want to sort a list , then use the following method:-
lst=[1,4,3,5,2]
lst.sort()#Put parameter reverse=True to sort in descending order
#lst is now equal to [1,2,3,4,5]
