[Tutor] run with default value if input not given

[Steven D'Aprano]

On Mon, Oct 29, 2012 at 11:28:05AM +0500, Saad Javed wrote:
> I've come up with this:
> 
> try:
> sys.argv[1]
> x = sys.argv[1]
> main(x)
> except IndexError:
> main(x)
> 
> It works but seems hackish.

There's no need to look up sys.argv[1] twice, nor any need to write 
main(x) in both blocks. You can do each once only:

try:
    # Always use the minimum code needed inside a try block.
    x = sys.argv[1]
except IndexError:
    x = "some default value"
main(x)


Here's yet another way:

args = sys.argv + ["some default value"]
main(args[1])



-- 
Steven