Sys.argv: command-line arguments start as text

Useful to know

sys.argv contains program arguments, with the initial element describing the script or invocation. A supplied quantity such as 12 starts as text, not an automatically validated number. [1]

A small example can read it after checking the argument count. For a more complex interface, argparse organizes conversion and help. An argument’s presence does not establish that its value is acceptable for the operation.