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

You’re calling a method or accessing a property that doesn’t exist on that type.

Fix 1: Check the type

# ❌ Strings don't have .append()
name = "Alice"
name.append(" Smith")  # AttributeError!

# ✅ Use the right method for the type
name = "Alice"
name = name + " Smith"  # Strings use concatenation

# Lists have .append()
items = ["Alice"]
items.append("Bob")

Fix 2: Check for typos

# ❌ Typo
my_list.apend("item")

# ✅ Correct spelling
my_list.append("item")

Fix 3: Variable is None

# ❌ Function returned None
result = my_list.sort()  # .sort() returns None!
result.append("item")    # AttributeError!

# ✅ .sort() modifies in place
my_list.sort()
my_list.append("item")

Common methods that return None: .sort(), .append(), .extend(), .reverse(), .clear().

Fix 4: Wrong import or module

# ❌ Imported the module, not the class
import json
data = json.loads(text)
data.loads(more_text)  # dict has no .loads()!

# ✅ json.loads() is on the module, not the result
more_data = json.loads(more_text)

Debugging tip

# Check what attributes exist
print(type(my_var))
print(dir(my_var))

See also: Python cheat sheet | Python NoneType not subscriptable fix