Descriptor 'append' for 'list' objects doesn't apply to a 'str' object

# Descriptor 'append' for 'list' objects doesn't apply to a 'str' object

The Python "TypeError: descriptor 'append' for 'list' objects doesn't apply to a 'str' object" occurs when we call the append() method on the list class.

To solve the error, call the method on an instance of the class instead, e.g. list().append('a').

Here is an example of how the error occurs.

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# ⛔️ TypeError: descriptor 'append' for 'list' objects doesn't apply to a 'str' object
list.append('hello')

# ⛔️ TypeError:
list.append(1)

We called the append method on the list class which caused the error.

# Call the append() method on a list object

Instead, call the append() method on a list object.

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my_list = list()

my_list.append('bobby')
my_list.append('hadz')
my_list.append('com')

print(my_list)  # 👉️ ['bobby', 'hadz', 'com']

We used parentheses to instantiate the list class and called the append() method on an instance of the class.

# Use square brackets to declare a variable that stores a list

Note that a much more common way to declare a variable that stores a list is to use square brackets.

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my_list = []

print(type(my_list))  # 👉️ <class 'list'>

my_list.append('bobby')
my_list.append('hadz')
my_list.append('com')

print(my_list)  # 👉️ ['bobby', 'hadz', 'com']

The example above achieves the same result.

The list.append() method adds an item to the end of the list.

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my_list = ['a', 'b', 'c']


my_list.append('d')

print(my_list)  # 👉️ ['a', 'b', 'c', 'd']

The method returns None as it mutates the original list.

Make sure to not store the result of calling list.append() in a variable.

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a_list = []

# ⛔️ don't do this
result = a_list.append('bobbyhadz.com')

print(result)  # 👉️ None

print(a_list) # 👉️ ['bobbyhadz.com']

Notice that the result variable stores a None value because the list.append() method mutates the original list and returns None.

# Appending multiple values to a list

If you need to append multiple values to a list, use the extend() method instead.

The list.extend method takes an iterable (such as a list) and extends the list by appending all of the items from the iterable.

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my_list = ['a', 'b']

my_list.extend(['c', 'd', 'e'])

print(my_list)  # 👉️ ['a', 'b', 'c', 'd', 'e']

The list.extend method returns None as it mutates the original list.

You can print the list class and an instance of the class to see the difference between the two.

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print(list)  # 👉️ <class 'list'>
print(list())  # 👉️ []

The first call to the print function prints the class, whereas the second prints an instance of the class.

You first have to instantiate the list class to use methods like append.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• How to Append a Dictionary to a List in Python
• How to append multiple Values to a List in Python
• Append value to List if not already present using Python
• Insert/Append an Element into a Tuple in Python