spectrochempy.Coord¶

class Coord(**kwargs)[source]¶

Explicit coordinates for a dataset along a given axis.

The coordinates of a NDDataset can be created using the Coord object. This is a single dimension array with either numerical (float) values or labels (str, Datetime objects, or any other kind of objects) to represent the coordinates. Only a one numerical axis can be defined, but labels can be multiple.

Parameters

data (ndarray, tuple or list) – The actual data array contained in the Coord object. The given array (with a single dimension) can be a list, a tuple, a ndarray , or a ndarray-like object. If an object is passed that contains labels, or units, these elements will be used to accordingly set those of the created object. If possible, the provided data will not be copied for data input, but will be passed by reference, so you should make a copy the data before passing it in the object constructor if that’s the desired behavior or set the copy argument to True.
**kwargs – Optional keywords parameters. See other parameters.

Other Parameters

dtype (str or dtype, optional, default=np.float64) – If specified, the data will be casted to this dtype, else the type of the data will be used.
dims (list of chars, optional.) – if specified the list must have a length equal to the number od data dimensions (ndim) and the chars must be taken among among x,y,z,u,v,w or t. If not specified, the dimension names are automatically attributed in this order.
name (str, optional) – A user friendly name for this object. If not given, the automatic id given at the object creation will be used as a name..
labels (array of objects, optional) – Labels for the data. labels can be used only for 1D-datasets. The labels array may have an additional dimension, meaning several series of labels for the same data. The given array can be a list, a tuple, a ndarray , a ndarray-like, a NDArray or any subclass of NDArray .
units (|Unit| instance or str, optional) – Units of the data. If data is a Quantity then units is set to the unit of the data; if a unit is also explicitly provided an error is raised. Handling of units use the pint package.
title (str, optional) – The title of the dimension. It will later be used for instance for labelling plots of the data. It is optional but recommended to give a title to each ndarray.
dlabel (str, optional) – Alias of title.
copy (bool, optional) – Perform a copy of the passed object. Default is False.
linear (bool, optional) – If set to True, the coordinate is considered as a LinearCoord object.
offset (float, optional) – Only used is linear is True. If omitted a value of 0.0 is taken for the coordinate offset.
increment (float, optional) – Only used if linear is true. If omitted a value of 1.0 is taken for the coordinate increment.

See also

NDDataset: Main SpectroChemPy object: an array with masks, units and coordinates.
LinearCoord: linear coordinates.

Examples

We first import the object from the api :

>>> from spectrochempy import Coord

We then create a numpy ndarray and use it as the numerical data axis of our new Coord object :

>>> c0 = Coord.arange(1., 12., 2., title='frequency', units='Hz')
>>> c0
Coord: [float64] Hz (size: 6)

We can take a series of str to create a non numerical but labelled axis :

>>> tarr = list('abcdef')
>>> tarr
['a', 'b', 'c', 'd', 'e', 'f']

>>> c1 = Coord(labels=tarr, title='mylabels')
>>> c1
Coord: [labels] [  a   b   c   d   e   f] (size: 6)

Methods

`Coord.amax`(dataset[, dim, keepdims])	Return the maximum of the dataset or maxima along given dimensions.
`Coord.amin`(dataset[, dim, keepdims])	Return the maximum of the dataset or maxima along given dimensions.
`Coord.arange`([start, stop, step, dtype])	Return evenly spaced values within a given interval.
`Coord.around`(dataset[, decimals])	Evenly round to the given number of decimals.
`Coord.astype`([dtype])	Cast the data to a specified type.
`Coord.copy`([deep, keepname])	Make a disconnected copy of the current object.
`Coord.fromfunction`(cls, function[, shape, ...])	Construct a nddataset by executing a function over each coordinate.
`Coord.fromiter`(iterable[, dtype, count])	Create a new 1-dimensional array from an iterable object.
`Coord.geomspace`(start, stop[, num, ...])	Return numbers spaced evenly on a log scale (a geometric progression).
`Coord.get_labels`([level])	Get the labels at a given level.
`Coord.is_units_compatible`(other)	Check the compatibility of units with another object.
`Coord.ito`(other[, force])	Inplace scaling to different units.
`Coord.ito_base_units`()	Inplace rescaling to base units.
`Coord.ito_reduced_units`()	Quantity scaled in place to reduced units, inplace.
`Coord.linspace`(cls, start, stop[, num, ...])	Return evenly spaced numbers over a specified interval.
`Coord.loc2index`(loc)	Return the index corresponding to a given location.
`Coord.logspace`(cls, start, stop[, num, ...])	Return numbers spaced evenly on a log scale.
`Coord.max`(dataset[, dim, keepdims])	Return the maximum of the dataset or maxima along given dimensions.
`Coord.min`(dataset[, dim, keepdims])	Return the maximum of the dataset or maxima along given dimensions.
`Coord.ptp`(dataset[, dim, keepdims])	Range of values (maximum - minimum) along a dimension.
`Coord.round`(dataset[, decimals])	Evenly round to the given number of decimals.
`Coord.round_`(dataset[, decimals])	Evenly round to the given number of decimals.
`Coord.to`(other[, inplace, force])	Return the object with data rescaled to different units.
`Coord.to_base_units`([inplace])	Return an array rescaled to base units.
`Coord.to_reduced_units`([inplace])	Return an array scaled in place to reduced units.

Attributes

`Coord.data`	The `data` array (`ndarray`).
`Coord.dimensionless`	True if the `data` array is dimensionless - Readonly property (bool).
`Coord.dtype`	Data type (np.dtype).
`Coord.filename`	Current filename for this dataset (`Pathlib` object).
`Coord.has_data`	True if the `data` array is not empty and size > 0.
`Coord.has_defined_name`	True is the name has been defined (bool).
`Coord.has_units`	True if the `data` array have units - Readonly property (bool).
`Coord.id`	Object identifier - Readonly property (str).
`Coord.is_empty`	True if the `data` array is empty or size=0, and if no label are present - Readonly property (bool).
`Coord.is_float`	True if the `data` are real values - Readonly property (bool).
`Coord.is_integer`	True if the `data` are integer values - Readonly property (bool).
`Coord.is_labeled`	True if the `data` array have labels - Readonly property (bool).
`Coord.labels`	An array of labels for `data` (`ndarray` of str).
`Coord.limits`	Range of the data (list).
`Coord.linear`	Flag to specify if the data can be constructed using a linear variation (bool).
`Coord.m`	The `data` array (`ndarray`).
`Coord.magnitude`	The `data` array (`ndarray`).
`Coord.meta`	Additional metadata (`Meta`).
`Coord.name`	A user-friendly name (str).
`Coord.offset`	Starting value for linear array
`Coord.reversed`	bool - Whether the axis is reversed (readonly property).
`Coord.roi`	Region of interest (ROI) limits (list).
`Coord.size`	Size of the underlying `data` array - Readonly property (int).
`Coord.spacing`	Return coordinates spacing.
`Coord.title`	An user friendly title (str).
`Coord.umasked_data`	The actual array with mask and unit (`Quantity`).
`Coord.unitless`	`bool` - True if the `data` does not have `units` (Readonly property).
`Coord.units`	`Unit` - The units of the data.
`Coord.value`	Alias of `values`.
`Coord.values`	`Quantity` - The actual values (data, units) contained in this object (Readonly property).