Fixing Python String Mismatch by Recognizing UTF-16BE File Encoding

Learn how to resolve Python string comparison issues caused by reading UTF-16BE encoded files instead of UTF-8, and how to correctly open and decode such files.
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This video is based on the question https://stackoverflow.com/q/79491259/ asked by the user 'Lilian Shi' ( https://stackoverflow.com/u/19223111/ ) and on the answer https://stackoverflow.com/a/79491273/ provided by the user 'user2357112' ( https://stackoverflow.com/u/2357112/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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The Problem: String Comparison Fails Despite Identical Printed Output

If you read lines from a file and try to compare them against a hardcoded string, you might find the comparison unexpectedly fails:

[[See Video to Reveal this Text or Code Snippet]]

Yet, printing both strings can show visibly identical content, leaving you puzzled.



Root Cause: File Encoding Is Not UTF-8

The underlying problem is usually a mismatch of encodings:

Your file is not UTF-8 encoded, but something else like UTF-16BE (big-endian).

Python reads the file assuming UTF-8 (the default) without complaints but misinterprets the bytes.

This results in unexpected null bytes (\x00) interspersed between characters.

For example, examining the bytes in your file's line might yield:

[[See Video to Reveal this Text or Code Snippet]]

This pattern of alternating null bytes strongly suggests UTF-16BE encoding.



How to Fix: Open File with Correct Encoding

To properly read the file, explicitly specify the UTF-16BE encoding when opening the file:

[[See Video to Reveal this Text or Code Snippet]]

This loads the file content correctly and makes string comparisons accurate.

Why Not UTF-8?

Opening the file with encoding='utf-8' doesn't work because the byte sequences do not conform to UTF-8's byte patterns.



Additional Recommendations

Check why your file is saved as UTF-16BE. Tools like Maven or your terminal may produce output files with non-standard encodings, especially on Windows.

If possible, configure the tool generating the file to produce UTF-8 output to avoid confusion and compatibility issues.



Summary

When string comparisons fail despite identical print output, suspect encoding issues.

Look for null byte patterns to guess UTF-16 encoding.

Use the correct file encoding (utf-16be) when opening files to fix encoding decoding problems.

Verify your tools' outputs to avoid non-UTF-8 file encodings.

By ensuring the file is read with the correct encoding, your string comparisons and regex matches will behave as expected.