[Tutor] string to binary and back... Python 3

[Jordan]

On 07/19/2012 08:53 PM, Prasad, Ramit wrote:
>>> I think your basic problem is too much conversion because you do not
>>> understand the types. A string is represented by a series of bytes
>>> which are binary numbers. Do you understand the concept behind ASCII?
>>> Each letter has a numeric representation that are sequential. So the
>>> string 'abcd' is equivalent to a series of bytes 65,66,67,68. It is
>>> not equivalent to 65666768 or 65+66+67+68. So your first task is to
>>> convert each character to the numeric equivalent and store them in a
>>> list. Once you have them converted to a list of integers, you can
>>> create another list that is a list of characters.
>> Sorry for the long delay in getting back to you, I got called to the field.
>> Thank you, I agree I do feel like I am doing too much conversion. I do
>> understand the concept behind ASCII at least enough to know about ord()
>> although I did for get about chr() which is ord()'s reverse function. I
>> had tried to break them down to the ordinal value, but I really do want
>> to get the integer and the data down to binary, as it provides an
>> advantage for the overall program that I am writing. Thank you for your
>> time.
> Why not explain your usecase? Technically, everything is binary
> on a computer so the question is why do *you* need to see the
> binary form? Anyway, you can get the binary string by doing
> `bin(ord(character))` and reverse it by doing 
> `chr(int(binary_string,2))`. [1]
OK. I am using one time pads to XOR data, but the one time pads (keys)
are very large numbers, converting them to binary increases their size
exponentially, which allows me to get more XORing done out of a single
key. I am XORing both files and strings so I need to have code that can
do both even if that means two branches of code via an if/else perhaps
with an isinstance(data, str).
I do not need to actually see the binary form.
> If you are doing some kind of XOR (I think your first email mentioned 
> it) then you can XOR integers. Unless you are doing some kind of 
> display of binary output, you usually do not need to actually see 
> the binary string as most binary manipulation can be done via the 
> integer value.
Agreed. Although the visual does help for validation (seeing is believing).
>  [1] - Thanks to Steven.
Yes thank you Steven. I am working on the code now to see if I can make
the above work for me, if I need further help I will be back.
Thank you all again for your time.
>
>
>
>
> Ramit
>
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