PromptHub
Back to Errors
Python Beginner 103 views

Python TabError

The code uses inconsistent indentation by mixing tabs and spaces.

Explanation

TabError is a subclass of IndentationError that specifically occurs when Python encounters a mix of tabs and spaces for indentation. Python 3 strictly prohibits mixing tabs and spaces - it treats them as different indentation levels and raises an error. A tab is typically equivalent to 8 spaces, so mixing them creates ambiguous indentation. This error is common when code is edited in different editors with different settings.

Common Causes

  • Mixing tabs and spaces in same file
  • Different editor settings
  • Copy-pasting from different sources
  • No .editorconfig enforcing consistency
  • Auto-indent using wrong character

Solution

Configure your editor to use spaces instead of tabs (PEP 8 recommends 4 spaces). Enable "convert tabs to spaces" in your editor settings. Use the "show whitespace" feature to see invisible characters. Run autopep8 or black to auto-format and fix indentation. Check your .editorconfig file to enforce consistent indentation across your team.

Code Example 

# Mixing tabs and spaces - TabError
def process():
    if True:
        print('spaces')  # 4 spaces
\tprint('tab')  # tab character - ERROR!

# Fix: use consistent indentation
def process():
    if True:
        print('spaces')  # 4 spaces
        print('also spaces')  # 4 spaces

# Check for mixed indentation
# In bash:
cat -A file.py | grep -n $'\t'  # find lines with tabs

# Or use Python's tabnanny
import tabnanny
tabnanny.check('file.py')  # reports files with mixed indentation

# Auto-fix with black
# pip install black
black file.py  # auto-formats entire file

# EditorConfig to enforce consistency
# .editorconfig:
[*]
indent_style = space
indent_size = 4

Error Information

Language

python

Difficulty

Beginner

Views

103

Related Errors

Python

Python SyntaxError

Python detected invalid syntax in the source code.
Python

Python RecursionError

The function calls itself too many times, exceeding the maximum recursion depth.
Python

Python AttributeError

The code tries to access an attribute or method that doesn't exist on an object.
Python

Python ModuleNotFoundError

Python cannot find the specified module in the installed packages or system path.
All tools