I can not figure out why my code is not working,
key_one= raw_input("Enter key (0 <= key <= 127): ")
if key_one in range(128):
bin_key_one=bin(key_one)[2:]
print bin_key_one
else:
print "You have to enter key (0 <= key <= 127)"
when i enter a number between 0 and 127, it keeps on going to the else! can some one tell me why?
raw_input returns a string and "93" is NOT in range(128).
To make sure you compare apples to apples, cast key_one to int:
key = int(raw_input("Enter key (0 <= key <= 127): "))
if key in range(128)
# if condition
else
# else condition
EDIT: Python documentation is awesome, so if you have questions, it's a great idea to train by reading the docs first.
If the prompt argument is present, it is written to standard output without a trailing newline. The function then reads a line from input, converts it to a string (stripping a trailing newline), and returns that. When EOF is read, EOFError is raised. - http://docs.python.org/library/functions.html#raw_input
raw_input will return a string, so your if comparison fails (you're comparing an int with a string). Try casting:
key_one = int(raw_input('enter key: '))
ifstatement,0 <= int(key_one) < 128will be way more efficient thanint(key_one) in range(128).