6.21.3.6 Standard option types

optparse has six built-in option types: string, int, long, choice, float and complex. If you need to add new option types, see section , Extending optparse.

Arguments to string options are not checked or converted in any way: the text on the command line is stored in the destination (or passed to the callback) as-is.

Integer arguments are passed to int() to convert them to Python integers. If int() fails, so will optparse, although with a more useful error message. (Internally, optparse raises OptionValueError; OptionParser catches this exception higher up and terminates your program with a useful error message.)

Likewise, float arguments are passed to float() for conversion, long arguments to long(), and complex arguments to complex(). Apart from that, they are handled identically to integer arguments.

choice options are a subtype of string options. The choices option attribute (a sequence of strings) defines the set of allowed option arguments. optparse.check_choice() compares user-supplied option arguments against this master list and raises OptionValueError if an invalid string is given.

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