How to Remove UnicodeError in Python

In many Python applications, you may encounter an error known as UnicodeError. Usually, this error occurs when you try encoding or decoding a string with an encoding that can’t handle some of the characters in the string.

This tutorial aims to help you understand this issue and how you can resolve it effectively.

Understanding the UnicodeError

Before you can fix any error, you must understand why and when it occurs. When you encounter a UnicodeError, it means Python has failed to encode or decode a string to bytes, usually because the string contains characters that are not part of a given encoding. The error could be a UnicodeEncodeError or a UnicodeDecodeError.

The encode error occurs when Python is unable to convert a Unicode string into its byte representation, primarily because the string contains characters not present in the specified ‘encoding’.

On the other hand, A decode error occurs when Python cannot convert a sequence of bytes into a string.

Fixing the UnicodeError

There are two main strategies you can use to fix this error:

  1. Change the String Encoding: This is the most effective fix. Python uses Unicode, which supports all languages and their characters. However, when you read or write in Python, it’s generally converted to or from bytes using a character set. If a character is not in that set, you get the UnicodeError. You can solve this problem by using UTF-8 encoding which supports all Unicode characters.
  2. Ignore or Replace Invalid Characters: If changing the encoding is not an option, you can instruct Python to ignore discarded characters or replace them with a substitute.

Tackling UnicodeEncodeError

Here is a simple way to handle UnicodeEncodeError:

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try:
    byte_string = unicode_string.encode('utf-8')
except UnicodeEncodeError:
    unicode_string = unicode_string.encode('utf-8', 'ignore')

Tackling UnicodeDecodeError

Here is a simple method to tackle UnicodeDecodeError:

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try:
    unicode_string = byte_string.decode('utf-8')
except UnicodeDecodeError:
    byte_string = byte_string.decode('utf-8', 'ignore')

Code Demonstration

Here is an example of a case that would raise a UnicodeError.

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# case that raises UnicodeEncodeError
unicode_string = '화이팅'
byte_string = unicode_string.encode('ascii')

And here is how you can fix it.

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# handling the error
try:
    byte_string = unicode_string.encode('ascii')
except UnicodeEncodeError:
    byte_string = unicode_string.encode('ascii', 'ignore')

Full Code

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# Case that raises UnicodeEncodeError
unicode_string = '화이팅'
try:
    byte_string = unicode_string.encode('ascii')
except UnicodeEncodeError:
    byte_string = unicode_string.encode('ascii', 'ignore')
 
# Case that raises UnicodeDecodeError
byte_string = b'\xed\x99\x94\xec\x9d\xb4\xed\x8c\x85'
try:
    unicode_string = byte_string.decode('ascii')
except UnicodeDecodeError:
    unicode_string = byte_string.decode('ascii', 'ignore')

Conclusion

As has been noted, UnicodeError in Python can be quite frustrating. However, once you understand the error’s cause, resolving it becomes much easier.

It’s mostly down to how you encode or decode your strings. The strategies mentioned above have been proven to work effectively. If a particular character set doesn’t support certain characters, consider using ‘utf-8’.

If changing the encoding is not an option, you could opt to ignore or replace the characters causing the error.