convert large string to binary

[jmark13]

In python I have a very large string of 0s and 1s. i.e '010100100101110101001...' etc.

I want to convert this to BINARY without first converting it to decimal. Then I want to take the resulting binary number and convert it to it's decimal equivalent. Fastest way possible because it is about 72k bits.

Thanks in advance.

OR, If anyone knows maple... How could I perform the python operation:

>string='010101010101'
stringB=string*5
>>print stringB
>'010101010101010101010101010101010101010101010101010101010101'

in Maple?? Its a new programing language for me, but I know how to do binary conversions in it.

-Mark

[griswolf]

Can you be a little more specific about what you mean by 'convert to binary'? What is the expected type of the result? Or do you just care that it be in some in-memory form so you can take the next step?

And: is that 74 Kbits the number of represented bits, or the size of the ascii string? (not that a 9.25 Kbit binary number is significantly less trouble than a 74 Kbit one)

Finally: What is the actual goal of this code? Do you actually need the internal representation later, or is the "decimal equivalent" all you really need, in the end?

[TrustyTony]

Like this:

>>> a='010101010101010101010101010101010101010101010101010101010101'
>>> a=int(a,2)
>>> a
384307168202282325L
>>>

[TrustyTony]

You wanted to express it also in binary format, so I continue

>>> bin(384307168202282325L)
'0b10101010101010101010101010101010101010101010101010101010101'
## from this alternative way
a='0b'+a
>>> eval(a)
384307168202282325L
>>>

[utpalendu]

#!/usr/bin/env python
def makebinary(number):
temp=long(number)
mask=1
k=0
for i in xrange(64):
mask= 1 << (64 - (i+1))
k= temp & mask
if k == 0:
print int("0"),
else:
print int("1"),

a='010101010101010101010101010101010101010101010101010101010101'
a=int(a,2)
print a
#makebinary(4)
makebinary(a)

[TrustyTony]

#!/usr/bin/env python

def makebinary(number):
        temp=long(number)
        mask=1
        k=0 
        for i in xrange(64):
          mask= 1 << (64 - (i+1))
          k= temp & mask
          if k == 0:
                   print int("0"),
          else:
                   print int("1"),
    
a='010101010101010101010101010101010101010101010101010101010101'
a=int(a,2)
print a
#makebinary(4)
makebinary(a)

You can not do this with that hand coded version:

>>> import random
>>> bindig='01'
>>> a=''.join([random.choice(bindig) for a in range(70*1024)])
>>> b=int(a,2)
>>> c=bin(b)
>>> print c[:100],a[:100]
0b11111111110001100010101111111111010100100001011010010111101101001100100011010001101001000111110010 1111111111000110001010111111111101010010000101101001011110110100110010001101000110100100011111001011
>>> print c[:100]; print a[:100]
0b11111111110001100010101111111111010100100001011010010111101101001100100011010001101001000111110010
1111111111000110001010111111111101010010000101101001011110110100110010001101000110100100011111001011
>>> print c[-100:]; print a[-100:]
1000100001011101101101001000001000101011111001110011001011110111001001100101010001000111011001100100
1000100001011101101101001000001000101011111001110011001011110111001001100101010001000111011001100100
>>> print len(c), len(a)
71682 71680
>>> ## bin puts extra 0b binary sign in front

[jmark13]

I'm sorry, I want to convert any large decimal *TO* binary not from binary.

The second question was specific to the language maple, not python. I know how to convert to binary in maple and I know how to extend strings in python... I just want to be able to do both in at least one of the two languages.

[TrustyTony]

I gave solution to that:

import random
bindigits='01'
a = ''.join([random.choice(bindigits) for a in range(80*1024)])
a = '0b1'+a ## bin string starting with 1

b = int(a,2) ## b as normal int
c = bin(b) ## convert BACK TO bin string repr

## comparision for checking of the process back and forth
print c[:100] ; print a[:100]
print c[-100:]; print a[-100:]
print len(c), len(a)

For processing check documentation of module decimal.

[TrustyTony]

Can you mark this case solved?

[jmark13]

Awesome thanks, tonyjv.