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Python Library Reference

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14.3.3.6 Standard option types

optparse has six built-in option types:string,int,long,choice,float andcomplex. If you need to add new optiontypes, see section 14.3.5, Extendingoptparse.

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

Integer arguments (typeint orlong) are parsed as follows:

• if the number starts with0x, it is parsed as a hexadecimal number

• if the number starts with0, it is parsed as an octal number

• if the number starts with0b, it is parsed as a binary number

• otherwise, the number is parsed as a decimal number

The conversion is done by calling eitherint() orlong() withthe appropriate base (2, 8, 10, or 16). If this fails, so willoptparse,although with a more useful error message.

float andcomplex option arguments are converted directly withfloat() andcomplex(), with similar error-handling.

choice options are a subtype ofstring options. Thechoicesoption attribute (a sequence of strings) defines the set of allowedoption arguments.optparse.check_choice() comparesuser-supplied option arguments against this master list and raisesOptionValueError if an invalid string is given.

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Python Library Reference

Previous:14.3.3.5 Option attributesUp:14.3.3 Reference GuideNext:14.3.3.7 Parsing arguments

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Release 2.5.2, documentation updated on 21st February, 2008.