AttributeError: 'str' object has no attribute 'append'

# AttributeError: 'str' object has no attribute 'append'

The Python "AttributeError: 'str' object has no attribute 'append'" occurs when we try to call the append() method on a string (e.g. a list element at specific index).

To solve the error, call the append method on the list or use the addition (+) operator if concatenating strings.

Here is an example of how the error occurs.

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a_str = 'bobbyhadz'

# ⛔️ AttributeError: 'str' object has no attribute 'append'
a_str.append('.com')

And here is another example of how the error occurs.

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

# ⛔️ AttributeError: 'str' object has no attribute 'append'
my_list[2].append('d')

We accessed the list element at index 2 before calling the append() method.

# Make sure to call the append() method on a list

To solve the error, call append() on the list instead.

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my_list = ['bobby', 'hadz', '.']

my_list.append('com')

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

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

The method returns None as it mutates the original list.

# Use the addition (+) operator when concatenating strings

If you are trying to concatenate strings, use the addition operator (+) instead.

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str_1 = 'bobby'

str_2 = 'com'

result = str_1 + 'hadz.' + str_2

print(result)  # 👉️ 'bobbyhadz.com'

The addition (+) operator can be used to concatenate strings.

Alternatively, you can use a formatted string literal.

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str_1 = 'bobby'

str_2 = '.com'

result = f'{str_1}hadz{str_2}'

print(result)  # 👉️ 'bobbyhadz.com'

Make sure to wrap expressions in curly braces - {expression}.

# Figure out where the variable got assigned a string

If you are trying to append an element to the end of a list, you have to figure out how the value you are calling append() on got assigned a string.

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

# 👇️ Reassigned the variable to a string by mistake
my_list = 'hello'

# ⛔️ AttributeError: 'str' object has no attribute 'append'
my_list.append('d')

We set the my_list variable to a list initially, but it later got set to a string which caused the error.

For example, calling the str.join() method on a list, joins the list into a string based on the provided separator.

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a_list = ['bobby', 'hadz', 'com']

a_str = ','.join(a_list)
print(a_str)  # 👉️ bobby,hadz,com

a_list = a_str.split(',')
print(a_list)  # 👉️ ['bobby', 'hadz', 'com']

a_list.append('new')

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

If you need to split the string into a list based on a separator, use the str.split() method and then call list.append().

The str.split() method splits the string into a list of substrings using a delimiter.

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print('bobby hadz com'.split(" "))  # 👉️ ['bobby', 'hadz', 'com']
print('bobby,hadz,com'.split(","))  # 👉️ ['bobby', 'hadz', 'com']

The method takes the following 2 parameters:

# How to debug your code

A good way to start debugging is to print(dir(your_object)) and see what attributes a string has.

Here is an example of what printing the attributes of a string looks like.

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my_string = 'hello world'

# [ 'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format',
#  'format_map', 'index', 'isalnum', 'isalpha', 'isascii', 'isdecimal', 'isdigit', 'isidentifier',
#  'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower',
#  'lstrip', 'maketrans', 'partition', 'removeprefix', 'removesuffix', 'replace', 'rfind', 'rindex',
#  'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase',
#  'title', 'translate', 'upper', 'zfill']
print(dir(my_string))

If you pass a class to the dir() function, it returns a list of names of the class's attributes and recursively of the attributes of its bases.

Since append() is not a method implemented by strings, the error is caused.

If the error persists, follow the instructions in my AttributeError: 'str' object has no attribute 'X in Python article.

# Additional Resources

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

• AttributeError: 'str' object has no attribute 'decode'
• AttributeError: 'str' object has no attribute 'get' (Python)
• AttributeError: 'str' object has no attribute 'strftime'