argv

1. In the previous homework, the program must prompt users to input the year and the month.
2. It is also possible for a user to supply that information at the command-line, for example, by typing "python cal.py 2014 11".
3. Python can retrieve the command-line arguments via the variable sys.argv. Please note that the script name is argv[0]. For example, in the example "python cal.py 2014 11",
   • argv[0] = "cal.py"
   • argv[1] = "2014"
   • argv[2] = "11"
4. To know how many arguments are passed to your program, you may apply the len() function on sys.argv.
5. Let argc denote the count of arguments. Modify your previous homework so that
   • if argc == 3:
     • Get year from sys.argv[1]
     • Get month from sys.argv[2]
   • if argc == 1
     • Prompt the user to input YYYY.MM
     • # This is the same as the original program.
   • else
     • Print a message to tell users the expected number of arguments.

$ python cal2.py 2014 11
November 2014
Su Mo Tu We Th Fr Sa
                   1
 2  3  4  5  6  7  8
 9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30