Hashing an array or object in python 3

Question

I want to hash a simple array of strings The documentation says you can't simple feed a string into hashlib's update() function, so I tried a regular variable, but then I got the TypeError: object supporting the buffer API required error.

Here's what I had so far

def generateHash(data):
    # Prepare the project id hash
    hashId = hashlib.md5()

    hashId.update(data)

    return hashId.hexdigest()

Answer 1

You can use the repr() function to get the (Unicode) string representation of the array (or of whatever object that implements conversion to a representation). Then you encode the string to UTF-8 (the order of bytes is the same everywhere when using UTF-8). The resulting bytes can be hashed as you tried above:

#!python3
import hashlib

def hashFor(data):
    # Prepare the project id hash
    hashId = hashlib.md5()

    hashId.update(repr(data).encode('utf-8'))

    return hashId.hexdigest()


if __name__ == '__main__':
    data1 = ['abc', 'de']
    data2 = ['a', 'bcde']
    print(hashFor(data1) + ':', data1)
    print(hashFor(data2) + ':', data2)

It prints on my console:

c:\tmp\___python\skerit\so17412304>py a.py
d26d27d8cbb7c6fe50637155c21d5af6: ['abc', 'de']
dbd5ab5df464b8bcee61fe8357f07b6e: ['a', 'bcde']