PyArg_ParseTuple() Cheat Sheet - danecross/PyNA62Analysis GitHub Wiki

The function signature for this method is as follows:

int PyArg_ParseTuple (PyObject *arg, const char *format, ...)

Argument descriptions:

• *arg is the python tuple of arguments.
• *format argument is the format string. More on this in 3 lines
• the remaining arguments are addresses for references in the format string

Format String

This is a string of characters which consists of zero or more "format units." Each unit describes one of the python objects in the *arg tuple by saying what Python type it is, and what C type it must be converted to.

There is a long list of these format units. I will list the ones I think will be relevant to us, for a quick reference. As in the documentation, (round) brackets describe the python type and [square] brackets describe the C type it will be translated to.

Strings and Buffers

• s (str)[const char *]
• s* (str or bytes-like obj)[Py_buffer]
• z (str or None)[const char *]

Numbers

• i (int)[int]
• I (int)[unsigned int]
• l (int)[long int]
• c (bytes or bytearray of len 1)[char]
• C (str of len 1)[int]
• f (float)[float]
• d (float)[double]
• D (complex)[Py_complex]

Objects and Misc.

• O (object)[PyObject *]
• O! (object)[typeobject, PyObject]
• p (bool)[int]
• (items) (tuple)[matching items]