Binary calculations

By Tony Veijalainen on Sep 10th, 2011 4:05 am

Very trivial program which could be thought as conclusion from the Quiz posts (thanks Gribouillis for inspiration for format)

from __future__ import print_function
try:
    input = raw_input
except:
    pass

from operator import iadd, imul, idiv, imod, isub

oper = dict(zip('+*/%-', (iadd, imul, idiv, imod, isub)))

def get_bin(prompt='Bin value'):
    while True:
        try:
            return int(input('%s: ' % prompt),2)
        except ValueError:
            print('Please  enter string of 0 or 1 digits')

def get_op(prompt='Give operator'):
    while True:
        try:
            op = input('%s (%s): ' % (prompt, ''.join(oper.keys()))).strip()
            assert op in oper
            return op
        except AssertionError:
            print('You must give one of the operators!')

if __name__ == '__main__':
    first = get_bin('Give first binary number')
    second = get_bin('Give second binary number')
    op = get_op()

    result = oper[op](first,second)
    
    fl = max(len(bin(b)) for b in (first, second, result))
    sl = fl - 2
    sep = '-' * fl
    print('''
    {first:>{fl}b}
    {op} {second:>{sl}b}
    {sep}
    {result:>{fl}b}
    '''.format(**locals()))

8 Months Ago

Interesting, however the get_op() method won't work if python is run in optimized mode (python -O) because this mode removes assert statements. Assert statements should not influence the program's flow of control, except for debugging purposes.

Gribouillis

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2,786 posts since Jul 2008

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8 Months Ago

Thanks, so then better to change to traditional if.. return there, also Python3 has not idiv(nor div), so I changed it to floordiv:

from __future__ import print_function
try:
    input = raw_input
except:
    pass

from operator import iadd, imul, floordiv, imod, isub

oper = dict(zip('+*/%-', (iadd, imul, floordiv, imod, isub)))

def get_bin(prompt='Bin value'):
    " input binary value with prompt (': ' added for you) "
    while True:
        try:
            return int(input('%s: ' % prompt),2)
        except ValueError:
            print('Please  enter string of 0 or 1 digits')

def get_op(prompt='Give operator'):
    """ input binary operator, which is in global oper dictionary
        (': ' added for you as is the list of valid operators)

    """
    while True:
        op = input('%s (%s): ' % (prompt, ''.join(oper.keys()))).strip()
        if op in oper:
            return op
        else:
            print('You must give one of the operators!')

if __name__ == '__main__':
    first = get_bin('Give first binary number')
    second = get_bin('Give second binary number')
    op = get_op()

    result = oper[op](first,second)
    
    fl = max(len(bin(b)) for b in (first, second, result))
    # get space for operator sign in second line
    sl = fl - 2
    sep = '-' * fl
    print('''
    {first:>{fl}b}
    {op} {second:>{sl}b}
    {sep}
    {result:>{fl}b}
    '''.format(**locals()))

pyTony

pyMod

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