Python Append List to a List Example

How to append a list to another list in Python? We are often required to append a list to another list to create a nested list. Python provides an append() method to append a list as an element to another list. In case you wanted to append elements from one list to another list, you can either use the extend() or insert() with for loop.

1. Quick Examples of Append List to a List

Following are quick examples of appending a list to another list.


# Append list into another list
languages1.append(languages2)

# Append multiple lists into another list
languages1.append([languages2,languages3])

# Append list elements to list
languages1.extend(languages2)

# Append List Elements using insert()
for x in languages2:
    languages1.insert(len(languages1),x)

2. Append List as an Element into Another List

To append the python list as an element into another list, you can use the append() from the list. This takes either string, number, or iterable as an argument and appends it at the end of the list.


# Consider two lists
languages1=['Python','PHP','Java',]
languages2=['C','C++','C#']
print("Language List 1: ",languages1)
print("Language List 2: ",languages2)

# Append list into another list
languages1.append(languages2)
print("Result: ",languages1)

This example yields the below output.

python list insert another list

Similarly, you can also append multiple lists to another list.


# Consider three lists
languages1=['Python','PHP','Java',]
languages2=['C','C++','C#']
languages3=["Scala","Ruby"]

print("Language List 1: ",languages1)
print("Language List 2: ",languages2)
print("Language List 3: ",languages3)

# Append multiple lists into another list
languages1.append([languages2,languages3])
print("Result: ",languages1)

Yields below output.


# Output:
Language List 1:  ['Python', 'PHP', 'Java']
Language List 2:  ['C', 'C++', 'C#']
Language List 3:  ['Scala', 'Ruby']
Result:  ['Python', 'PHP', 'Java', [['C', 'C++', 'C#'], ['Scala', 'Ruby']]]

3. Append List Elements to Another List

If you wanted to append the individual element from one list to another list you can use the extend(). This method takes the list as an argument and extends the list to separate elements and appends to the list.


# Consider two lists
languages1=['Python','PHP','Java',]
languages2=['C','C++','C#']
print("Language List 1: ",languages1)
print("Language List 2: ",languages2)

# Append List Elements into Another List
languages1.extend(languages2)
print("Result: ",languages1)

Yields below output.


# Output:
Language List 1:  ['Python', 'PHP', 'Java']
Language List 2:  ['C', 'C++', 'C#']
Result:  ['Python', 'PHP', 'Java', 'C', 'C++', 'C#']

Similarly, you can also get this output by using + operator * unpack and many more. Refer to append multiple elements to the list.

4. Using Looping with insert()

Finally, you can also achieve this by using the insert() with for loop. This is used to append a single element at a time at a specific position. Here, we will loop through the languages2 list and each element is appended to the languages1 at the end. len(languages2) returns the count of the list which is used to specify the end position.


# Consider two lists
languages1=['Python','PHP','Java',]
languages2=['C','C++','C#']
print("Language List 1: ",languages1)
print("Language List 2: ",languages2)

# Append list elements using insert()
for x in languages2:
    languages1.insert(len(languages1),x)
print("Result: ",languages1)

This yields the same output as above.

Conclusion

In this article, you have learned how to append the whole list as an item or element to another list using append() and also learned appending elements from one list to another using extend() and other approaches.

NNK

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