Python - Insert list in another list

When working with lists in Python, you often need to insert one list into another. Python provides several methods to accomplish this: append(), extend(), insert(), and list concatenation with + operator.

Using append() Method

The append() method adds the entire second list as a single element ?

first_list = [1, 2, 3, 4, 5]
second_list = [6, 7, 8, 9, 10]

first_list.append(second_list)
print("Using append():", first_list)

Using append(): [1, 2, 3, 4, 5, [6, 7, 8, 9, 10]]

Using extend() Method

The extend() method adds each element of the second list individually ?

third_list = [11, 12, 13, 14, 15]
fourth_list = [16, 17, 18, 19, 20]

third_list.extend(fourth_list)
print("Using extend():", third_list)

Using extend(): [11, 12, 13, 14, 15, 16, 17, 18, 19, 20]

Using insert() Method

The insert() method allows you to insert a list at a specific position ?

numbers = [1, 2, 5, 6]
middle_numbers = [3, 4]

# Insert at index 2
numbers[2:2] = middle_numbers
print("Using slice insertion:", numbers)

# Alternative with insert() for single element
fruits = ['apple', 'banana', 'orange']
fruits.insert(1, 'grape')
print("Using insert():", fruits)

Using slice insertion: [1, 2, 3, 4, 5, 6]
Using insert(): ['apple', 'grape', 'banana', 'orange']

Using + Operator (Concatenation)

The + operator creates a new list without modifying the original lists ?

list1 = [1, 2, 3]
list2 = [4, 5, 6]

combined = list1 + list2
print("Original list1:", list1)
print("Combined list:", combined)

Original list1: [1, 2, 3]
Combined list: [1, 2, 3, 4, 5, 6]

Comparison

Conclusion

Use extend() to merge list elements, append() to add a list as a nested element, and + operator to create new combined lists without modifying originals.