Passing integer lists to python

Question

I want to pass 2 lists of integers as input to a python program.

For e.g, (from command line)

python test.py --a 1 2 3 4 5 -b 1 2  

Answer 1

If the only arguments are the lists and the separators, you can do it relatively simply:

sa = sys.argv.index('-a')
sb = sys.argv.index('-b')
lista = [int(i) for i in sys.argv[sa+1:sb]]
listb = [int(i) for i in sys.argv[sb+1:]]

Adding validation is easy:

aval = [i for i in lista if i>1 and i<50]
if len(aval) < len(lista):
    print 'The -a list contains invalid numbers.'
bval = [i for i in listb if i>1 and i<50]
if len(bval) < len(listb):
    print 'The -b list contains invalid numbers.'

Producing a help message:

if sys.argv[1] in ['-h', '-H'] or len(sys.argv) == 1:
    print "Usage:  -a [list of integers] -b [list of integers]"