Python add to beginning of list

You can use the insert() method or the + Operator to add to the beginning of the list in Python. The insert() function inserts an element to the given index of an existing list.

insert(idx, value)

Using the + operator on two or more lists combines them in the specified order. If you add list1 + list2 together, then it concatenates all the elements from list2 after the last element of list1.

Python adds to the beginning of the list

A simple example code appends an element to the front of a list in Python. Notice the to_insert variable is encapsulated with square brackets [].

lst = [1, 2, 3]

# insert 24 at 0 index
lst.insert(0, 24)
print(lst)

# concatenates
lst = [100] + lst
print(lst)

Output:

Use the list.insert(0, x) element to insert the element x at the first position 0 in the list. All elements j>0 will be moved by one index position to the right.

Using prepend() method (if available):

# Note: Python does not have a built-in prepend method, but you can define one for convenience.

def prepend(lst, element):
    return [element] + lst

my_list = [2, 3, 4, 5]
element_to_add = 1

my_list = prepend(my_list, element_to_add)

print(my_list)

In this example, a custom prepend() function is defined, which creates a new list with the desired element added at the beginning.

Do comment if you have any doubts or suggestions on this Python list topic.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.