how to input variable into a python script while opening from cmd prompt?

Question

I am wondering how would one get variables inputted in a python script while opening from cmd prompt? I know using c one would do something like:

int main( int argc, char **argv ) {
    int input1 = argv[ 0 ]
    int input2 = argv[ 1 ]

.....

}

how can I achieve the same kind of result in python?

Answer 1

import sys

def main():
   input1 = sys.argv[1]
   input2 = sys.argv[2]
...

if __name__ == "__main__":
   main()

Answer 2

The arguments are in sys.argv, the first one sys.argv[0] is the script name.

For more complicated argument parsing you should use argparse (for python >= 2.7). Previous modules for that purpose were getopts and optparse.

Answer 3

There are two options.

1. import sys.argv and use that.
2. Use getopts

See also: Dive into Python and PMotW

Answer 4

it is also useful to determine option specific variables

''' \
USAGE:  python script.py -i1 input1 -i2 input2
    -i1 input1 : input1 variable
    -i2 input2 : input2 variable
'''

import sys 
...

in_arr = sys.argv
if '-i1' not in in_arr  or '-i2' not in in_arr:
    print (__doc__)
    raise NameError('error: input options are not provided')
else:
    inpu1 = in_arr[in_arr.index('-i1') + 1]
    inpu2 = in_arr[in_arr.index('-i2') + 1]
...

# python script.py -i1 Input1 -i2 Input2