To add an element or item to a python list, append()
method is used. This method takes a single argument and adds this value to the end of list.
append()
method accepts a single parameter and returns None
.
Syntax of
append()
method is
list.append(element)
element
is added to the end of the list. If the list already contains element, still the element
is appended to the list and it becomes duplicate in the list.
Note that append()
modifies the original list.
append() example
Below is an example of append()
method in python list.
# create a list l = [1,2,3] print('Original List:',l) # add an element l.append(4); # print list print('List after appending:',l) # add existing element l.append(1) # print list again print('List after appending again:',l)
This produces following output
Just like you can add a single element to a list with
append()
, it can also be used to add an entire list as an element to a list. Example,
# create a list l1 = [1, 2, 3] # create another list l2 = ['a', 'b', 'c'] # add second list to first one l1.append(l2) print('Updated List:122`',l1)
This will add the second list, as it is, to the end of first list. This means that the last list element will be a list instead of a single element as evident from the below output.
Updated list: [1, 2, 3, [a, b, c]]
Notice the last element is enclosed between square brackets which means that it is a list. If you check the type of the last element using type()
function, then you get <class 'list'>
.
If you want all elements of the second list to be appended to the first list, then use extend() method of list.