line
is a bytestring, because you opened the file in binary mode. You'll need to decode the string; if it is a date string matching the pattern, you can simply use ASCII:
time.strptime(line.decode('ascii'), '%Y-%m-%d ...')
You can add a 'ignore'
argument to ignore anything non-ASCII, but chances are the line won't fit your date format then anyway.
Note that you cannot pass a value that contains more than the parsed format in it; a line with other text on it not explicitly covered by the strptime()
pattern will not work, whatever codec you used.
And if your input really varies that widely in codecs, you'll need to catch exceptions one way or another anyway.
Aside from UTF-16 or UTF-32, I would not expect you to encounter any codecs that use different bytes for the arabic numerals. If your input really mixes multi-byte and single-byte codecs in one file, you have a bigger problem on your hand, not in the least because newline handling will be majorly messed up.