[Tutor] How can I convert hex string to binary string?

[Kirby Urner]

On Wednesday 03 April 2002 03:17 am, Ares Liu wrote:
> def hex2bin(str):
>    bin = ['0000','0001','0010','0011',
>          '0100','0101','0110','0111',
>          '1000','1001','1010','1011',
>          '1100','1101','1110','1111']
>    aa = ''
>    for i in range(len(str)):
>       aa += bin[atoi(str[i],base=16)]
>    return aa

Good one.  Use of list index to access pre-computed strings, vs.
actually computing base 2 values over and over, seems a good
idea.

Slightly simpler (style point: best to not use str as a variable name,
as it's also a built-in function):

#
# hex2bin
#
def hex2bin(hexno):
   bin = ['0000','0001','0010','0011',
         '0100','0101','0110','0111',
         '1000','1001','1010','1011',
         '1100','1101','1110','1111']
   base2 = ''
   for d in hexno:
      base2 += bin[int(d,base=16)]
   return base2

Kirby