Solving 'ASCII' Codec Encoding Issues with Characters

This guide will help you understand and resolve common UnicodeEncodeError issues that arise when encoding non-ASCII characters in Python. The guide will provide valuable and relevant information to developers, including step-by-step solutions and an FAQ section.

Table of Contents

Understanding UnicodeEncodeError

A UnicodeEncodeError occurs when you try to encode a Unicode string into a byte string using a codec that does not support the Unicode characters in the string. The error message usually takes the following format:

UnicodeEncodeError: 'ascii' codec can't encode character u'\xfc' in position 5: ordinal not in range(128)

In this example, the error occurs because the 'ASCII' codec cannot encode the character 'ü' (u'\xfc' in Unicode). The ASCII encoding supports only 128 characters, which include the basic Latin alphabet, digits, and some punctuation marks.

Common Causes of UnicodeEncodeError

  • Reading or writing text files containing non-ASCII characters without specifying the correct encoding.
  • Combining Unicode strings with byte strings containing non-ASCII characters.
  • Using str() function on Unicode objects containing non-ASCII characters.
  • Passing Unicode objects containing non-ASCII characters to functions or libraries that expect byte strings.

Solutions to Fix UnicodeEncodeError

Solution 1: Explicitly Specify the Correct Encoding

When reading or writing text files containing non-ASCII characters, always specify the correct encoding. For example, use UTF-8 encoding, which supports a wide range of Unicode characters:

with open('example.txt', 'r', encoding='utf-8') as file:
    content =

Solution 2: Use Unicode Literals

When working with non-ASCII characters in your code, use Unicode literals by adding a 'u' prefix to the string:

unicode_string = u'Hello, 你好, Привет!'

Solution 3: Encoding and Decoding

When combining Unicode strings with byte strings or using functions or libraries that expect byte strings, use the encode() and decode() methods to convert between Unicode and byte strings:

# Unicode to byte string
unicode_string = u'Hello, 你好, Привет!'
byte_string = unicode_string.encode('utf-8')

# Byte string to Unicode
decoded_string = byte_string.decode('utf-8')


1. What is the difference between Unicode and ASCII?

ASCII is a character encoding standard that uses 7 bits to represent 128 characters, including the basic Latin alphabet, digits, and some punctuation marks. Unicode is a more extensive character encoding standard that supports over 143,000 characters, including characters from various languages, symbols, and emojis. In Python, Unicode strings are represented using the str type in Python 3 and the unicode type in Python 2.

2. What is the default encoding in Python?

The default encoding in Python is usually 'ASCII' in Python 2 and 'UTF-8' in Python 3. You can check the default encoding by importing the sys module and accessing the sys.getdefaultencoding() function:

import sys

3. Can I change the default encoding in Python?

Yes, you can change the default encoding using the reload() function from the sys module:

import sys

However, changing the default encoding is generally not recommended, as it can lead to unexpected behaviors and compatibility issues. It is better to explicitly specify the encoding when needed.

4. How can I convert a byte string containing non-ASCII characters to a Unicode string?

You can use the decode() method with the appropriate encoding to convert a byte string containing non-ASCII characters to a Unicode string:

byte_string = b'Hello, \xe4\xbd\xa0\xe5\xa5\xbd, \xd0\x9f\xd1\x80\xd0\xb8\xd0\xb2\xd0\xb5\xd1\x82!'
unicode_string = byte_string.decode('utf-8')

5. How can I handle UnicodeEncodeError exceptions in my code?

You can use a try-except block to catch UnicodeEncodeError exceptions and handle them gracefully, such as by logging the error, displaying a user-friendly message, or using a fallback encoding:

    # Code that may raise a UnicodeEncodeError
except UnicodeEncodeError as e:
    print(f'Error: {e}')
    # Handle the error, e.g., use a different encoding, log the error, etc.

Great! You’ve successfully signed up.

Welcome back! You've successfully signed in.

You've successfully subscribed to

Success! Check your email for magic link to sign-in.

Success! Your billing info has been updated.

Your billing was not updated.