all Python 3localefunction

locale.getpreferredencoding()

encoding

Returns the encoding open() uses for text files without encoding=; in UTF-8 mode it is always 'utf-8'.

Syntax

locale.getpreferredencoding(do_setlocale=True)

This is where 'on Windows the file opened as cp1251' comes from: without encoding=, open() asks this function, so one program reads the same file differently on different machines. Since 3.15 UTF-8 mode is on by default and the answer became 'utf-8', yet an explicit encoding='utf-8' remains the only portable choice. The default do_setlocale=True may call setlocale() temporarily, which is not thread-safe, so pass False.

Examples

import locale
print(locale.getpreferredencoding(False))  # → ? utf-8 или cp1251 — зависит от машины
with open('note.txt', 'w', encoding='utf-8') as f:  # явная кодировка не зависит от машины
    f.write('привет')
with open('note.txt', encoding='utf-8') as f:
    print(f.read())  # → привет

See also

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