all Python 3filecmpfunction

filecmp.cmp()

comparing files

Compares two files and returns True if they are considered equal; by default it trusts size and modification time.

Syntax

filecmp.cmp(f1, f2, shallow=True) -> bool

With shallow=True (the default) files with the same type, size and mtime are declared equal WITHOUT reading their content — after a time-preserving copy or an edit within the same second that is a false True. Only shallow=False is guaranteed to compare content. Results are cached, and a missing file raises FileNotFoundError rather than returning False.

Examples

import filecmp, os
open('a.txt', 'w').write('hello')
open('b.txt', 'w').write('jello')
st = os.stat('a.txt')
os.utime('b.txt', ns=(st.st_atime_ns, st.st_mtime_ns))  # то же время
print(filecmp.cmp('a.txt', 'b.txt'))  # → True — сравнили только размер и время
print(filecmp.cmp('a.txt', 'b.txt', shallow=False))  # → False

See also

Common errors

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