Re: [Tutor] Binary/Decimal convertor
On 11/01/13 21:51, Ghadir Ghasemi wrote:
Hi, I made a program called binary/denary convertor.
Can anyone tell me about how I could stop the user entering a binary
> number with more than 8 numbers or 8 bit
Why would you want to? Your code can handle much bigger binary numbers,
why limit the user to 8 bits?
Here is the code. I started off by entering 'len' function.
num1 = int(input('please enter the first 8 bit binary number: '),2)
Here hyou read the number as a string and already convert it to a real
number in Python. So the conversion from binary has already happened
regardless of how long the string was.
if len(num1) > 8:
print("please enter an 8 bit binary number")
You now try to see how long the number is, but numvers don;t have a length.
So to do what you claim you want you need to do the len() check before
you do the inty() conversion.
Something like:
num1 = input('please enter the first 8 bit binary number: ')
if len(num1) > 8:
print("please enter an 8 bit binary number")
else:
num = int(num,2)
Then put that in while a loop that repeats until the length is <=8
return int(num1,2)
And here you return which would terminate your function except you don't
have a function so it will give a syntax error. And trying to convert a
num as a binary won't work because its already stored internally as a
binary number. This only works if you still have the string as described
above.
num2 = int(input('please enter the second 8 bit binary number: '),2)
And this doesn't do any len() checks
result = add_binary_numbers(num1, num2)
print('the result is', bin(result)[2:])
I'd suggest that you make your add_binary_numbers() function return
the binary string. Otherwise it doesn't add any value over the
standard plus sign...
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
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Re: [Tutor] Binary/Decimal convertor
On 01/11/2013 04:51 PM, Ghadir Ghasemi wrote:
> Hi, I made a program called binary/denary convertor. Can anyone tell me about
> how I could stop the user entering a binary number with more than 8 numbers
> or 8 bit by repeating the question over and over until they do enter a
> correct binary number( 8-bit or less)
> Here is the code. I started off by entering 'len' function.
>
> def add_binary_numbers(num1, num2):
> return num1 + num2
>
> num1 = int(input('please enter the first 8 bit binary number: '),2)
> if len(num1) > 8:
> print("please enter an 8 bit binary number")
> return int(num1,2)
> num2 = int(input('please enter the second 8 bit binary number: '),2)
> result = add_binary_numbers(num1, num2)
> print('the result is', bin(result)[2:])
>
>
1. Specify the Python version. I'll assume version 3.3
2. Show whatever error you got. I'd guess something like the following:
File "", line 1, in
TypeError: object of type 'int' has no len()
The len() function operates on strings, lists, and other sequences and
mappings. But although you had a string at first, you've already
converted it to an int, which has no len() method. It might be simplest
to compare the value num to 0 and 255. Alternatively, you could compare
it before doing the int function.
Since you're doing it twice, it probably makes sense to do this in a
function. Write a function that repeatedly asks the user till it gets a
value in the right range.
The other error that jumps out is that you have a return statement at
top-level, while the statement only makes sense inside a function. That
problem goes away once you put the input logic inside a function.
--
DaveA
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Re: [Tutor] Binary/Decimal convertor
* Ghadir Ghasemi [2013-01-11 21:51]:
> Hi, I made a program called binary/denary convertor. Can anyone tell
> me about how I could stop the user entering a binary number with more
> than 8 numbers or 8 bit by repeating the question over and over until
> they do enter a correct binary number( 8-bit or less) Here is the
> code. I started off by entering 'len' function.
>
> def add_binary_numbers(num1, num2):
> return num1 + num2
>
> num1 = int(input('please enter the first 8 bit binary number: '),2)
> if len(num1) > 8:
> print("please enter an 8 bit binary number")
> return int(num1,2)
> num2 = int(input('please enter the second 8 bit binary number: '),2)
> result = add_binary_numbers(num1, num2)
> print('the result is', bin(result)[2:])
It looks like the first thing you need to do is figure out how to use a
loop (eg, while loop, for loop). I would recommend thinking about some
pseudocode to determine your program's flow and then try to build
something to accomplish that.
--
David Rock
da...@graniteweb.com
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