1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
# This file connects ASDF to the astropy.table.Table class
import asdf
from astropy.io import registry as io_registry
from astropy.table import Table
def read_table(filename, data_key=None, find_table=None, **kwargs):
"""
Read a `~astropy.table.Table` object from an ASDF file
By default, this function will look for a Table object with the key of
``data`` in the top-level ASDF tree. The parameters ``data_key`` and
``find_key`` can be used to override the default behavior.
This function is registered as the Table reader for ASDF files with the
unified I/O interface.
Parameters
----------
filename : str or :class:`py.path:local`
Name of the file to be read
data_key : str
Optional top-level key to use for finding the Table in the tree. If not
provided, uses ``data`` by default. Use of this parameter is not
compatible with ``find_table``.
find_table : function
Optional function to be used for locating the Table in the tree. The
function takes a single parameter, which is a dictionary representing
the top of the ASDF tree. The function must return a
`~astropy.table.Table` instance.
Returns
-------
table : `~astropy.table.Table`
`~astropy.table.Table` instance
"""
if data_key and find_table:
raise ValueError("Options 'data_key' and 'find_table' are not compatible")
with asdf.open(filename, **kwargs) as af:
if find_table:
return find_table(af.tree)
else:
return af[data_key or "data"]
def write_table(table, filename, data_key=None, make_tree=None, **kwargs):
"""
Write a `~astropy.table.Table` object to an ASDF file.
By default, this function will write a Table object in the top-level ASDF
tree using the key of ``data``. The parameters ``data_key`` and
``make_tree`` can be used to override the default behavior.
This function is registered as the Table writer for ASDF files with the
unified I/O interface.
Parameters
----------
table : `~astropy.table.Table`
`~astropy.table.Table` instance to be written
filename : str or :class:`py.path:local`
Name of the new ASDF file to be created
data_key : str
Optional top-level key in the ASDF tree to use when writing the Table.
If not provided, uses ``data`` by default. Use of this parameter is not
compatible with ``make_tree``.
make_tree : function
Optional function to be used for creating the ASDF tree. The function
takes a single parameter, which is the `~astropy.table.Table` instance
to be written. The function must return a `dict` representing the ASDF
tree to be created.
"""
if data_key and make_tree:
raise ValueError("Options 'data_key' and 'make_tree' are not compatible")
if make_tree:
tree = make_tree(table)
else:
tree = {data_key or "data": table}
with asdf.AsdfFile(tree) as af:
af.write_to(filename, **kwargs)
def asdf_identify(origin, filepath, fileobj, *args, **kwargs):
return filepath is not None and filepath.endswith(".asdf")
try:
io_registry.register_reader("asdf", Table, read_table)
io_registry.register_writer("asdf", Table, write_table)
io_registry.register_identifier("asdf", Table, asdf_identify)
except io_registry.IORegistryError:
# This means we're using an older version of astropy
# and it has already claimed the 'asdf' identifier.
pass
|
