[Tutor] command line list arguments

[Peter Otten]

Garry Willgoose wrote:

> I want to input a python list as a command line argument as for example
> 
> python weathering-sens.py -daughter ['p0-50-50','p0-0-0-100’]
> 
> but what I get from sys.argv is [p0-50-50,p0-0-0-100] without the string
> delimiters on the list elements. I’m probably missing something really
> simple because sys.argv returns strings and probably strips the string
> delimiters in that conversion … but is there any way that I can keep the
> string delimiters so that inside the code I can just go (if arg is
> ['p0-50-50','p0-0-0-100’])
> 
> a=eval(arg)
> 
> or is there no alternative to doing this
> 
> python weathering-sens.py -daughter 'p0-50-50’ 'p0-0-0-100’
> 
> and doing the legwork of interpreting all the arguments individually (I’ve
> seen an example of this on the web).

With argparse it's really not that much legwork:

$ cat weathering-sens.py 
import argparse
parser = argparse.ArgumentParser()
parser.add_argument("-d", "--daughter", nargs="+")
args = parser.parse_args()
print(args.daughter)

$ python weathering-sens.py -d foo bar
['foo', 'bar']

$ python weathering-sens.py --daughter p0-50-50 p0-0-0-100
['p0-50-50', 'p0-0-0-100']

Note that args.daughter is a list of strings -- no need for eval().