[Tutor] enhanced subtration in an exponent

[Danny Yoo]

On Apr 21, 2015 12:24 AM, "Jim Mooney" <cybervigilante at gmail.com> wrote:
>
> Why does the compiler choke on this? It seems to me that the enhanced
> subtraction resolves to a legitimate integer in the exponent, but I get a
> syntax error:
>
> B = '11011101'
> sum = 0
> start = len(B)
> for char in B:
>     sum += int(char) * 2**(start -= 1) ## syntax error

Assignment is a statement.  In Python,  statements can't be composed.  In
the last line, it looks like you're trying to do two assignments, in
incrementing 'sum' and decrementing 'start'.  Try separating that into two
separate statements.