[Tutor] Conversion question

[Tom Green]

Thanks I just happened to find the site myself.  I guess I have to pass each
character to the function and build the 8-bit ASCII string or is there a
better way to do it?

On Tue, Jun 16, 2009 at 3:37 PM, Wayne <srilyk at gmail.com> wrote:

> On Tue, Jun 16, 2009 at 2:25 PM, Tom Green <xchimeras at gmail.com> wrote:
>
>> Correct 8-bit ASCII.  Sorry about that.  I am using Python 2.5.2, which
>> doesn't support bin.  If I upgraded how would I go about converting the
>> entire string to 8-bit ASCII?
>>
>> I appreciate your help.
>
>
>  you write the conversion yourself. anks
>
>
>
>
>    1. # convert a decimal (denary, base 10) integer to a binary string (base 2)
>
>    2. # tested with Python24   vegaseat    6/1/2005
>    3.
>    4. def Denary2Binary(n):
>
>    5.     '''convert denary integer n to binary string bStr'''
>    6.
>        bStr = ''
>    7.     if n < 0:  raise ValueError, "must be a positive integer"
>
>    8.     if n == 0: return '0'
>    9.     while n > 0:
>
>    10.         bStr = str(n % 2) + bStr
>    11.         n = n >> 1
>
>    12.     return bStr
>    13.
>    14. def int2bin(n, count=24):
>
>    15.     """returns the binary of integer n, using count number of digits"""
>    16.     return "".join([str((n >> y) & 1) for y in range(count-1, -1, -1)])
>
>    17.
>    18. # this test runs when used as a standalone program, but not as an imported module
>    19.
>    # let's say you save this module as den2bin.py and use it in another program
>    20. # when you import den2bin the __name__ namespace would now be  den2bin  and the
>
>    21. # test would be ignored
>    22. if __name__ == '__main__':
>    23.     print Denary2Binary(255)  # 11111111
>    24.
>
>    25.     # convert back to test it
>    26.     print int(Denary2Binary(255), 2)  # 255
>
>    27.
>    28.     print
>    29.
>    30.     # this version formats the binary
>
>    31.     print int2bin(255, 12)  # 000011111111
>
>    32.     # test it
>    33.     print int("000011111111", 2)  # 255
>
>    34.
>    35.     print
>    36.
>    37.     # check the exceptions
>
>    38.     print Denary2Binary(0)
>    39.     print Denary2Binary(-5)  # should give a ValueError
>
>
> from http://www.daniweb.com/code/snippet285.html#
>
> HTH,
> Wayne
>
>
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