A data conversion question

[Peter Otten]

Mok-Kong Shen wrote:

> A newbie's question of curiosity:
> 
> If I have
> 
> g=[1,[2]] and
> 
> bg=bytearray(str(g),"latin-1")
> 
> could I somehow get back from bg a list g1 that is the same as g?

Not for arbitrary values, but for lists, ints, and a few other types that's 
not a problem:

>>> g = [1, [2]]
>>> bg = bytearray(str(g), "latin-1")
>>> bg
bytearray(b'[1, [2]]')
>>> import ast
>>> ast.literal_eval(bg.decode("latin-1"))
[1, [2]]

See also https://docs.python.org/dev/library/ast.html#ast.literal_eval

Note that while eval() instead of ast.literal_eval() would also work you 
should avoid it. eval() can execute arbitrary Python code and is thus a big 
security whole when applied to user-provided data.