UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa0 in position ???: invalid start byte

Question

I am working with byte strings that include non-ASCII characters, specifically Hebrew text, and I encountered a UnicodeDecodeError when trying to decode the byte string to UTF-8. Here's the problematic code:

t = b'\xd7\x91\xd7\x9c\xd7\xa9\xd7\x95\xd7\xa0\xd7\x99\xd7\xaa:\xa0 '
print(t.decode('utf8'))

The error message I receive is:

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa0 in position 15: invalid start byte

From my understanding, the byte 0xa0 represents a non-breaking space in some encodings, but it seems to cause a problem in UTF-8 decoding. How can I correctly decode this byte string, especially when it contains mixed content like Hebrew characters and potential non-breaking spaces?

Is there a specific method or workaround in Python to handle such scenarios where non-standard or extended ASCII characters (like non-breaking spaces) are embedded within UTF-8 encoded byte strings?

Answer 1

The issue you encountered with the UnicodeDecodeError arises because the byte 0xa0 is not recognized as a valid UTF-8 sequence on its own. This byte often represents a non-breaking space in encodings such as ISO-8859-1 or Windows-1252 but is not valid in UTF-8 without proper preceding bytes.

When you use errors="ignore" in your decode method:

print(t.decode('utf8', errors="ignore"))

This tells Python to ignore parts of the byte string that it cannot decode properly. In the case of your string, Python skips over the 0xa0 byte because it cannot be decoded to UTF-8, and proceeds to decode the rest of the bytes, which are valid UTF-8 representations of Hebrew characters.

The output:

בלשונית:

Another option is errors='replace', which will replace undecodable bytes with the official Unicode replacement character � (U+FFFD):