List methods

Append

lst.append(elem)

Adds the specified element (elem) to the end of the list

>>> l = [1, 2, 3, 4, 5]
>>> l.append(0)
>>> l
[1, 2, 3, 4, 5, 0]

The append method in the above example added the element 0 to the end of the list.

Index

lst.index(elem)

Returns the position of the first occurrence of the specified element (elem).

>>> l = [1,2,3,4,5,3,3]
>>> l.index(3)
2

The index method in the above example returned the index of the first occurrence of the element 3 which is 2 in zero-based indexing.

Insert

lst.insert(pos, elem)

Inserts the specified element (elem) at the specified position (pos)

>>> l = [1,2,3,4,5]
>>> l.insert(3, 0)
>>> l
[1, 2, 3, 0, 4, 5]

The insert method in the above example inserted the element 0 at the index 3 (zero-based indexing) and thus the list now contains the element 0 at the index 3.

Pop

lst.pop(pos)

Removes and returns the element at the specified position. The pos parameter is optional. If it is not specified then the default value of pos is -1 and it removes the last element

>>> l = [1,2,3,4,5]
>>> l.pop(3)
4
>>> l
[1, 2, 3, 5]
>>> l.pop()
5
>>> l
[1, 2, 3]

In the first example, the pop method is used with a parameter that specifies the index at which the element needs to be removed. So in the first example, pop method removed and returned the element at index 3 (zero-based indexing) which is 4. In the second example, when no parameter is given to the pop method, it removes and returns the last element in the list.

Reverse

lst.reverse()

Reverses the order of the elements in the list. Note that it doesn’t return anything—it just modifies the list in place.

>>> l = [4,7,2,0,9]
>>> l.reverse()
>>> l
[9, 0, 2, 7, 4]

The reverse method in the above example reversed the order of the elements in the given list.