BrowseCatalog

class gdt.core.heasarc.BrowseCatalog(cache_path, table=None, verbose=True, cached=False)

Bases: object

A class that interfaces with the HEASARC Browse API. This can be called directly, but is primarily intended as a base class.

This class makes a query to HEASARC’s w3query.pl perl script in BATCHRETRIEVALCATALOG mode. All fields and rows are retrieved so that this class, on instantiation, contains the full set of catalog data. Any queries based on row or columns selections/slices are then done locally, instead of making repeated requests to the HEASARC. A cached copy of the catalog is saved locally so future instantiations can utilize the local copy instead of querying HEASARC.

Parameters:

• cache_path (str) – The path where the cached catalog will live.

• cached (bool, optional) – Set to True to read from the cached file instead of querying HEASARC. Default is False.

• table (str, optional) – The name of the table to be passed to the w3query.pl script.

• verbose (bool, optional) – Default is True

Attributes Summary

columns	The names of the columns available in the table
num_cols	The total number of columns (fields) in the data table
num_rows	The total number of rows in the data table

Methods Summary

column_range(column)	Return the data range for a given column, in the form of (low, high).
get_table([columns])	Return the table data as a numpy record array.
slice(column[, lo, hi])	Perform row slices of the data table based on a conditional of a single column.
slices(columns)	Perform row slices of the data table based on a conditional of multiple columns.

Attributes Documentation

columns

The names of the columns available in the table

Type:

(np.array)

num_cols

The total number of columns (fields) in the data table

Type:

(int)

num_rows

The total number of rows in the data table

Type:

(int)

Methods Documentation

column_range(column)

Return the data range for a given column, in the form of (low, high).

Parameters:

column (str) – The column name

Returns:

(tuple)

get_table(columns=None)

Return the table data as a numpy record array.

Parameters:

columns (list of str, optional) – The columns to return. If omitted, returns all columns.

Returns:

(np.recarray)

slice(column, lo=None, hi=None)

Perform row slices of the data table based on a conditional of a single column. Returns a new BrowseCatalog object.

Parameters:

• column (str) – The column name

• lo (optional) – The minimum (inclusive) value of the slice. If not set, uses the lowest range of the data in the column.

• hi (optional) – The maximum (inclusive) value of the slice. If not set, uses the highest range of the data in the column.

Returns:

(BrowseCatalog)

slices(columns)

Perform row slices of the data table based on a conditional of multiple columns. Returns a new BrowseCatalog object.

Parameters:

columns (list of tuples) – A list of tuples, where each tuple is (column, lo, hi). The ‘column’ is the column name, ‘lo’ is the lowest bounding value, and ‘hi’ is the highest bouding value. If no low or high bounding is desired, set to None. See slice() for more info.

Returns:

(BrowseCatalog)