Why is a None appearing in my output?

[Hugh Macdonald]

----- Original Message ----- 
From: "David Stockwell" <winexpert at hotmail.com>
To: <python-list at python.org>
Sent: Wednesday, May 12, 2004 8:46 PM
Subject: Why is a None appearing in my output?


> I entered the following text into a 'module file' and saved it:
> 
> def fib6(n):    # write Fibonacci series up to n
>     a, b = 0, 1
>     while b < n:
>         print  b,
>         a, b = b, a+b
>     else:
>         print "done b[",b,"], n[",n,"], a[", a,"]"
> 
> print "fib6:", fib6(50), "---"
> print "next"

What it's doing is this:

print "fib6:",
run fib6(50)
print b various times
print "done b[",b,"], n[",n,"], a[", a,"]"
print what was returned from fib6(50) (in this case None)
print "---"
print "next"

Your best bet would be to change the line:

print "fib6:", fib6(50), "---"

to

print "fib6:",
fib6(50),
print "---"

OR change the function itself to:

def fib6(n):    # write Fibonacci series up to n
    a, b = 0, 1
    while b < n:
        print  b,
        a, b = b, a+b
    return "done b[",b,"], n[",n,"], a[", a,"]"



Hugh Macdonald