register_identifier

astropy.io.registry.register_identifier(data_format, data_class, identifier, force=False)[source]

Associate an identifier function with a specific data type.

Parameters:
data_format : str

The data format identifier. This is the string that is used to specify the data type when reading/writing.

data_class : classobj

The class of the object that can be written.

identifier : function

A function that checks the argument specified to read or write to determine whether the input can be interpreted as a table of type data_format. This function should take the following arguments:

  • origin: A string "read" or "write" identifying whether the file is to be opened for reading or writing.
  • path: The path to the file.
  • fileobj: An open file object to read the file’s contents, or None if the file could not be opened.
  • *args: Positional arguments for the read or write function.
  • **kwargs: Keyword arguments for the read or write function.

One or both of path or fileobj may be None. If they are both None, the identifier will need to work from args[0].

The function should return True if the input can be identified as being of format data_format, and False otherwise.

force : bool, optional

Whether to override any existing function if already present. Default is False.

Examples

To set the identifier based on extensions, for formats that take a filename as a first argument, you can do for example:

>>> def my_identifier(*args, **kwargs):
...     return isinstance(args[0], str) and args[0].endswith('.tbl')
>>> register_identifier('ipac', Table, my_identifier)