[Tutor] interacting with stderr

[Alan Gauld]

On 30/08/14 23:31, Bo Morris wrote:

> time to a more appropriate amount. Anyone see any issues with it or ways
> to make it better?

One obvious issue:

> while True:
>      while count < 15:
>          for line in p.stderr:
 >              if  "Segmentation" in line:
>                  while restart < 3:
>                      for line in p.stderr:
>              if "storing 0x" in line:
>                  while restart < 3:
>                      for line in p.stderr:
>                          print line
>          if count == 15:
>              break
>      break

First, there are a lot of embedded loops in there, that's usually a 
design warning that maybe you need to look at things again. In 
particular I'm suspicious of those two "for line in p.stderr" loops
inside a loop that is itself a "for line in p.stderr" loop.
That feels wrong. I haven't worked through the detail so it
might be valid but it smells bad to me.
Looking closer, you are reassigning p in the middle of a loop that 
depends on p. That's usually not a good idea...

Second, the last break does nothing except terminate the outer loop 
after the first time through. So you might as well miss out the
initial "while True" line...

-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.flickr.com/photos/alangauldphotos