hashlib_update.py

#!/usr/bin/env python

# this is from The Python
# Standard Library by example
# ISBN13: 9780321767349

import hashlib

from hashlib_data import lorem

h = hashlib.md5()
h.update(lorem)
all_at_once = h.hexdigest()


def chunkize(size, text):
    "Return parts of the text in size-based increments."
    start = 0
    while start < len(text):
        chunk = text[start:start + size]
        yield chunk
        start += size
    return

h = hashlib.md5()
for chunk in chunkize(64, lorem):
    h.update(chunk)
line_by_line = h.hexdigest()

print 'All at once  :', all_at_once
print 'Line by line :', line_by_line
print 'Same         :', (all_at_once == line_by_line)