python - How can I improve the functionality of this code -

a1 = input("enter 8 bit  binary number convert: ")  a1 = list(a1)  ok = false;  if a1[0] == '0':     ok = true  if a1[0] == '1':     ok = true  if a1[1] == '0':     ok = true  if a1[1] == '1':     ok = true  if a1[2] == '0':     ok = true  if a1[2] == '1':     ok = true  if a1[3] == '0':     ok = true  if a1[3] == '1':     ok = true  if a1[4] == '0':     ok = true  if a1[4] == '1':     ok = true  if a1[5] == '0':     ok = true  if a1[5] == '1':     ok = true  if a1[6] == '0':     ok = true  if a1[6] == '1':     ok = true  if a1[7] == '0':     ok = true  if a1[7] == '1':     ok = true  if ok == true:     print("number binary!")   n1 = 0  if a1[7] == '1':     n1 = 1  if a1[6] == '1':     n1 = n1 + 2  if a1[5] == '1':     n1 = n1 + 4  if a1[4] == '1':     n1 = n1 + 8  if a1[3] == '1':     n1 = n1 + 16  if a1[2] == '1':     n1 = n1 + 32  if a1[1] == '1':     n1 = n1 + 64  if a1[0] == '1':     n1 = n1 + 128  print("denary number is: " + str(n1)) 

use set:

a1 = input("enter 8 bit  binary number convert: ")  if set(a1) <= set('01'):     print("number binary!") 

this true if set(a1) subset of set('01'):

>>> set('10011') <= set('01') true >>> set('10011abc') <= set('01') false 

you can use exceptions (and int() binary -> integer conversion):

try:     n1 = int(a1, 2) except valueerror:     print("not binary") else:     print("number binary")     print("denary number is: {}".format(n1)) 

this has added advantage of converting binary input integer in 1 step.

if don't want or can use int(), convert loop , use << left-shift each binary digit, , | binary bitwise or add new digit:

n1 = 0 digit in a1:     n1 = (n1 << 1) | (1 if digit == '1' else 0) 

this rather round-about way number, @ least using binary logic now.