# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""Table helper utilities."""
import numpy as np
from astropy.table import Table
from astropy.units import Quantity
from .units import standardise_unit
__all__ = [
"hstack_columns",
"table_standardise_units_copy",
"table_standardise_units_inplace",
"table_row_to_dict",
"table_from_row_data",
]
[docs]def hstack_columns(table, table_other):
"""Stack the column data horizontally
Parameters
----------
table : `~astropy.table.Table`
Input table
table_other : `~astropy.table.Table`
Other input table
Returns
-------
stacked : `~astropy.table.Table`
Stacked table
"""
stacked = Table()
for column in table.colnames:
data = np.hstack([table[column].data[0], table_other[column].data[0]])
stacked[column] = data[np.newaxis, :]
return stacked
[docs]def table_standardise_units_copy(table):
"""Standardise units for all columns in a table in a copy.
Calls `~gammapy.utils.units.standardise_unit`.
Parameters
----------
table : `~astropy.table.Table`
Input table (won't be modified)
Returns
-------
table : `~astropy.table.Table`
Copy of the input table with standardised column units
"""
# Note: we could add an `inplace` option (or variant of this function)
# See https://github.com/astropy/astropy/issues/6098
table = Table(table)
return table_standardise_units_inplace(table)
[docs]def table_standardise_units_inplace(table):
"""Standardise units for all columns in a table in place."""
for column in table.columns.values():
if column.unit:
column.unit = standardise_unit(column.unit)
return table
[docs]def table_row_to_dict(row, make_quantity=True):
"""Make one source data dict.
Parameters
----------
row : `~astropy.table.Row`
Row
make_quantity : bool
Make quantity values for columns with units
Returns
-------
data : `dict`
Row data
"""
data = {}
for name, col in row.columns.items():
val = row[name]
if make_quantity and col.unit:
val = Quantity(val, unit=col.unit)
data[name] = val
return data
[docs]def table_from_row_data(rows, **kwargs):
"""Helper function to create table objects from row data.
Works with quantities.
Parameters
----------
rows : list
List of row data (each row a dict)
"""
table = Table(**kwargs)
if len(rows) == 0:
return table
colnames = list(rows[0].keys())
for name in colnames:
coldata = [_[name] for _ in rows]
if isinstance(rows[0][name], Quantity):
coldata = Quantity(coldata, unit=rows[0][name].unit)
table[name] = coldata
return table