add add_meta_to_table

csst_common/io.py

@@ -21,6 +21,7 @@ from copy import deepcopy
 from typing import Optional
 
 from astropy.io import fits
+from astropy import table
 
 from .time import now
 
@@ -332,3 +333,27 @@ def get_proc_info(**kwargs):
         cards.append((k, v, ""))
     header = fits.Header(cards=cards)
     return reformat_header(header, comment="PROCESSING INFORMATION")
+
+
+def add_meta_to_table(t: table.Table, meta: dict) -> table.Table:
+    """Add meta information to a table.
+
+    Parameters
+    ----------
+    t : Table
+        Table.
+    meta : dict
+        Meta information.
+    """
+    # determine number of rows
+    n_rows = len(t)
+    # extract subset of meta information
+    sub_meta = {
+        "healpix": meta["healpix"],
+        "data_uuid": meta["data_uuid"],
+    }
+    # create meta table
+    t_meta = table.Table([sub_meta] * n_rows, dtype=("i4", "U36"))
+    # add meta columns to table
+    t.add_columns(t_meta.columns)
+    return t

tests/test_io.py

@@ -13,6 +13,7 @@ import os
 import unittest
 
 from astropy.io import fits
+from astropy import table
 
 from csst_common.io import (
     append_header,
@@ -22,6 +23,7 @@ from csst_common.io import (
     generate_meta,
     append_meta,
     extract_meta,
+    add_meta_to_table,
 )
 
 
@@ -143,3 +145,9 @@ class TestFitsHeaderOps(unittest.TestCase):
         self.assertIn("META", set(hdulist[0].header.keys()))
         meta = extract_meta(hdulist)
         self.assertEqual(meta["obs_id"], "123456")
+
+    def test_add_meta_to_table(self):
+        t = table.Table([{"a": 1, "b": 2}] * 5)
+        meta = generate_meta(obs_id="123456")
+        t = add_meta_to_table(t, meta)
+        self.assertEqual(set(t.colnames), ("a", "b", "healpix", "data_uuid"))