Data Points

class sacc.data_types.DataPoint(data_type, tracers, value, ignore_missing_tags=False, **tags)

A class for a single data point (one scalar value).

Data points have a type, zero or more tracers, a value, and any arbitrary tags that are stored in a dictionary, and can be used to describe angular scales, window functions, or any arbitrary information to be attached to the data.

Data points can be automatically created and added to a Sacc object, so you don’t normally nee to manually create them.

Parameters:

data_type: str

A string, indicating the type of data point

tracers: tuple

Tuple of strings with the names of tracers to use

value: float

Mean value of this statistics

tags: dict

Dictionary of further data point metadata, such as binning info, angles, etc.

Methods

from_table(table[, lookups])	Convert a table back into a list of data points.
get_tag(tag[, default])	Get the value of the the named tag, or None if not found.
to_table(data[, lookups])	Convert a list of data points to a single homogenous table

classmethod from_table(table, lookups=None)

Convert a table back into a list of data points.

This method removes null values from the tags.

Parameters:

table: astropy.table.Table

A table of data containing the tracers, values, and tags

lookups: dict

A dictionary of tags->dict showing replacements to make in the tags. Default is empty.

Returns:

data: list

list of DataPoint objects

get_tag(tag, default=None)

Get the value of the the named tag, or None if not found.

Parameters:

tag: str

Tag to find on the data point

default: any

Value to return if the tag is not found

Returns:

value: any

Value of the tag in this data point

classmethod to_table(data, lookups=None)

Convert a list of data points to a single homogenous table

Since data points can have varying tags, this method uses null values to represent non-present tags.

Parameters:

data: list

A list of DataPoint objects

lookups: dict

A dictionary of tags->dict showing replacements to make in the tags. Default is empty.

Returns:

table: astropy.table.Table

table object containing data points

sacc.data_types.build_data_type_name(sources, properties, statistic, subtype=None)

Parameters:

sources: str or list[str]

type(s) of astrophysical sources to which this applies

properties: str or list[str]

feature(s)/characterisic(s) of those sources/fields to which the statistic applies

statistic_type: str

mathematical type of the statistic

statistic_subtype: str or None

optional additional specifier. Default is None

Returns:

name: str

Type name of the form:

{sources}_{properties}_{statistic_type}[_{statistic_subtype}]

sacc.data_types.parse_data_type_name(name)

Parse a verbose data type name into its component parts Verbose data type names take the form: {sources}_{properties}_{statistic_type}[_{statistic_subtype}] where sources and properties are camel-case if there is more than one of them

Parameters:

name: str

A data type name

Returns:

sources: list[str]

type(s) of astrophysical sources to which this applies

properties: list[str]

feature(s)/characterisic(s) of those sources/fields to which the statistic applies

statistic_type: str

mathematical type of the statistic

statistic_subtype: str or None

optional additional specifier

class sacc.data_types.parsedDataTypeName(sources, properties, statistic, subtype)

Attributes:

properties

Alias for field number 1

sources

Alias for field number 0

statistic

Alias for field number 2

subtype

Alias for field number 3

Methods

count(value, /)	Return number of occurrences of value.
index(value[, start, stop])	Return first index of value.

properties

Alias for field number 1

sources

Alias for field number 0

statistic

Alias for field number 2

subtype

Alias for field number 3