Doc/libgetopt.tex

   1 \section{Standard Module \sectcode{getopt}}
   2
   3 \stmodindex{getopt}
   4 This module helps scripts to parse the command line arguments in
   5 \code{sys.argv}.
   6 It uses the same conventions as the \UNIX{}
   7 \code{getopt()}
   8 function.
   9 It defines the function
  10 \code{getopt.getopt(args, options)}
  11 and the exception
  12 \code{getopt.error}.
  13
  14 The first argument to
  15 \code{getopt()}
  16 is the argument list passed to the script with its first element
  17 chopped off (i.e.,
  18 \code{sys.argv[1:]}).
  19 The second argument is the string of option letters that the
  20 script wants to recognize, with options that require an argument
  21 followed by a colon (i.e., the same format that \UNIX{}
  22 \code{getopt()}
  23 uses).
  24 The return value consists of two elements: the first is a list of
  25 option-and-value pairs; the second is the list of program arguments
  26 left after the option list was stripped (this is a trailing slice of the
  27 first argument).
  28 Each option-and-value pair returned has the option as its first element,
  29 prefixed with a hyphen (e.g.,
  30 \code{'-x'}),
  31 and the option argument as its second element, or an empty string if the
  32 option has no argument.
  33 The options occur in the list in the same order in which they were
  34 found, thus allowing multiple occurrences.
  35 Example:
  36
  37 \bcode\begin{verbatim}
  38 >>> import getopt, string
  39 >>> args = string.split('-a -b -cfoo -d bar a1 a2')
  40 >>> args
  41 ['-a', '-b', '-cfoo', '-d', 'bar', 'a1', 'a2']
  42 >>> optlist, args = getopt.getopt(args, 'abc:d:')
  43 >>> optlist
  44 [('-a', ''), ('-b', ''), ('-c', 'foo'), ('-d', 'bar')]
  45 >>> args
  46 ['a1', 'a2']
  47 >>>
  48 \end{verbatim}\ecode
  49
  50 The exception
  51 \code{getopt.error = 'getopt error'}
  52 is raised when an unrecognized option is found in the argument list or
  53 when an option requiring an argument is given none.
  54 The argument to the exception is a string indicating the cause of the
  55 error.