Lists

 

List manipulation methods and functions

len(list)

It returns the length of the list, i.e. the number of elements in the list.

l=[1,2,3,4]

print(len(l))

Output

4

list.index(item)

It returns the index of the first matched item from the list.

l=[1,2,3,4]

print(l.index(3))

Output

2

list.append(item)

It adds an item at the end of a list

l=[1,2,3,4]

l.append(5)

print(l)

OR

l=[1,2,3,4]

a=5

l.append(a)

print(l)

Output

[1,2,3,4,5]

list.extend(item)

It adds multiple items at the end of a list.

l=[1,2,3,4]

l.extend([5,6,7,8])

print(l)

OR

l=[1,2,3,4]

a=[5,6,7,8]

l.extend(a)

print(l)

Output

[1, 2, 3, 4, 5, 6, 7, 8]

list.insert(position, item)

This function is used to insert a particular item/element at a given index

l=[1,2,3,4]

l.insert(3,5)

print(l)

Output

[1, 2, 3, 5, 4]

list.pop(index)

This pop() is used to remove a certain item at the specified index from the list

l=[1,2,3,4]

l.pop(2)

print(l)

Output

[1, 2, 4]

list.remove(value)

The remove() method is used to remove an element from the list by specifying the element

l=[1,2,3,4]

l.remove(2)

print(l)

Output

[1, 3, 4]

list.clear()

This method removes all the items from the list and the list becomes an empty list. This function does not return anything

l=[1,2,3,4]

l.clear()

print(l)

Output

[]

list.count(item)

This method returns the number of occurrences of the specified element in the list

l=[1,2,3,4,3]

print(l.count(3))

Output

2

list.reverse()

This function reverses the order of items  in the list

l=[1,2,3,4]

l.reverse()

print(l)

Output

[4,3,2,1]

list.sort()

It sorts the items into ascending order by default. To arrange them in decreasing order, the funtion will be list.sort(reverse=True)

l=[1,3,4,2]

l.sort()

print(l)

Output

[1, 2, 3, 4]

max(list)

It returns the item with maximum value 

l=[1,2,3,4]

print(max(l))

Output

4

min(list)

It returns the item with minimum value 

l=[1,2,3,4]

print(min(l))

Output

1

sum(list)

It returns the sum of the elements in the list

l=[1,2,3,4]

print(sum(l))

Output

10