Ask user for binary number
 

Hi I am trying to ask the user to input a binary number and checking to see if
the input contains 0's and 1's. If not, I want to inform the user that the input was invalid and ask them to retry.

Any help to fix my code would be greatly appreciated.

binary = int(raw_input("Enter a binary number:"))

for i in range(binary):

    if (binary != 0 or binary != 1):

        print "Invalid input"

        binary = int(raw_input("Enter a binary number:"))

Re: Ask user for binary number
 

binary = int(raw_input("Enter a binary number:"))

for i in range(binary):

    print "for loop is testing", i, "in range", binary

    if (binary != 0 or binary != 1):

        print binary, "not equal to 0 or 1"

        binary = int(raw_input("Enter a binary number:"))

    else:

       print binary, "equal to 0 or 1"

Re: Ask user for binary number
 

You could use list comprehension as well

binary = raw_input()

if False in [f == '0' or f == '1' for f in binary]:

        print "Not Binary"

else:

        print "Is Binary"

Re: Ask user for binary number
 

still_testing = True

while still_testing:

   bin = raw_input("\nEnter a binary number: ")

   if len(bin):

      still_testing = False

   for num in bin:

       if int(num) not in [0, 1]:

           print "Invalid input for", num

           still_testing = True

Re: Ask user for binary number
 

Not to be too terribly picky, but the code in the above post where it uses

if int(num) not in [0,1]:

will fail if the user enters non-digit characters.

If the test were performed with strings it would not fail:

if num not in ['0','1']: