[Tutor] trivial simple program..can it be made more concise?

[Steven D'Aprano]

On Sat, Feb 14, 2015 at 03:17:28AM +0000, steve10brink at comcast.net wrote:
> Hi all, 
> 
> I was playing with Python tonight and created a simple program that 
> outputs numbers counting up then counting down all on the same 
> terminal line. The code is as follows:
> 
> #------------------------------------------------------------ 
> a = 320000 #number to count up to 
> 
> for i in range (a): 
>     print i, '\r', 
> 
> for i in range ((a-1),0,-1): 
>     print i, '\r', 
> 
> #------------------------------------------------------------ 
> 
> It works as desired. However, I was trying to figure out a way to make 
> it more concise but cannot see a way since the 'range' parameters must 
> be integers (no functions allowed?).


Parameters to range can be anything which evaluates to integers, but 
I'm not sure how that will help you. Also, in Python 2 xrange is a 
little more efficient than range.

How's this?

a = 320000
counts = (xrange(a), xrange(a-1, 0, -1))
for counter in counts:
    for i in counter:
        print i, '\r'


BUT I'm not sure why you are worried about making it more concise when 
your code doesn't do what you want, as far as I can tell. You want the 
counter to be written on the same line, not 640 thousand lines, but when 
I try it, I get each number written to a different line.

Try this instead:

import sys
a = 320000
counts = (xrange(a), xrange(a-1, 0, -1))
for counter in counts:
    for i in counter:
        sys.stdout.write(str(i) + '\r')
        sys.stdout.flush()


-- 
Steve