Python 3.11+hashlibfunction

hashlib.file_digest()

hashing

A file's hash in one call: it reads a file opened in binary mode chunk by chunk and returns a ready hash object.

Syntax

hashlib.file_digest(fileobj, digest, /)

It replaces the manual loop of f.read(65536) and update(), and memory use does not depend on the file size. A file opened in text mode is rejected with ValueError — you need 'rb'. It returns an object, not a string: call hexdigest() next. Closing the file is the caller's job, so put the call inside with.

Examples

import hashlib
with open('data.bin', 'wb') as f:
    f.write(b'hello world')
with open('data.bin', 'rb') as f:
    digest = hashlib.file_digest(f, 'sha256')
print(digest.hexdigest()[:16])  # → b94d27b9934d3e08

import hashlib
with open('data.txt', 'w') as f:
    f.write('hello world')
with open('data.txt') as f:
    try:
        hashlib.file_digest(f, 'sha256')
    except ValueError:
        print('нужен режим rb')  # → нужен режим rb

See also

Common errors

Open in the full glossarydocs.python.orgReport an inaccuracy