holoviews.util Package

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util Package

class holoviews.util.Dynamic(*, kwargs, link_dataset, link_inputs, operation, shared_data, streams, name)

Bases: ParameterizedFunction

Dynamically applies a callable to the Elements in any HoloViews object. Will return a DynamicMap wrapping the original map object, which will lazily evaluate when a key is requested. By default Dynamic applies a no-op, making it useful for converting HoloMaps to a DynamicMap.

Any supplied kwargs will be passed to the callable and any streams will be instantiated on the returned DynamicMap. If the supplied operation is a method on a parameterized object which was decorated with parameter dependencies Dynamic will automatically create a stream to watch the parameter changes. This default behavior may be disabled by setting watch=False.

operation = param.Callable(allow_refs=False, label=’Operation’, nested_refs=False, rx=<param.reactive.reactive_ops object at 0x304d29410>)

Operation or user-defined callable to apply dynamically

kwargs = param.Dict(allow_refs=False, class_=<class ‘dict’>, default={}, label=’Kwargs’, nested_refs=False, rx=<param.reactive.reactive_ops object at 0x304d31bd0>)

Keyword arguments passed to the function.

link_inputs = param.Boolean(allow_refs=False, default=True, label=’Link inputs’, nested_refs=False, rx=<param.reactive.reactive_ops object at 0x30454bf10>)

If Dynamic is applied to another DynamicMap, determines whether linked streams and links attached to its Callable inputs are transferred to the output of the utility. For example if the Dynamic utility is applied to a DynamicMap with an RangeXY, this switch determines whether the corresponding visualization should update this stream with range changes originating from the newly generated axes.

link_dataset = param.Boolean(allow_refs=False, default=True, label=’Link dataset’, nested_refs=False, rx=<param.reactive.reactive_ops object at 0x304e09190>)

Determines whether the output of the operation should inherit the .dataset property of the input to the operation. Helpful for tracking data providence for user supplied functions, which do not make use of the clone method. Should be disabled for operations where the output is not derived from the input and instead depends on some external state.

shared_data = param.Boolean(allow_refs=False, default=False, label=’Shared data’, nested_refs=False, rx=<param.reactive.reactive_ops object at 0x3049af6d0>)

Whether the cloned DynamicMap will share the same cache.

streams = param.ClassSelector(allow_refs=False, class_=(<class ‘list’>, <class ‘dict’>), default=[], label=’Streams’, nested_refs=False, rx=<param.reactive.reactive_ops object at 0x3047bb850>)

List of streams to attach to the returned DynamicMap

classmethod instance(**params)

Return an instance of this class, copying parameters from any existing instance provided.

class holoviews.util.OptsMeta(name, bases, dict_)

Bases: ParameterizedMetaclass

Improve error message when running something like: ‘hv.opts.Curve()’ without a plotting backend.

property abstract

Return True if the class has an attribute __abstract set to True. Subclasses will return False unless they themselves have __abstract set to true. This mechanism allows a class to declare itself to be abstract (e.g. to avoid it being offered as an option in a GUI), without the “abstract” property being inherited by its subclasses (at least one of which is presumably not abstract).

get_param_descriptor(param_name)

Goes up the class hierarchy (starting from the current class) looking for a Parameter class attribute param_name. As soon as one is found as a class attribute, that Parameter is returned along with the class in which it is declared.

mro()

Return a type’s method resolution order.

holoviews.util.examples(path='holoviews-examples', verbose=False, force=False, root='/Users/runner/work/holoviews/holoviews/holoviews/util/__init__.py')

Copies the notebooks to the supplied path.

class holoviews.util.extension(*, name)

Bases: extension

Helper utility used to load holoviews extensions. These can be plotting extensions, element extensions or anything else that can be registered to work with HoloViews.

The plotting extension is the most commonly used and is used to select the plotting backend. The plotting extension can be loaded using the backend name, e.g. ‘bokeh’, ‘matplotlib’ or ‘plotly’.

Examples

Activate the bokeh plotting extension:

`python import holoviews as hv hv.extension("bokeh") `

classmethod instance(**params)

Return an instance of this class, copying parameters from any existing instance provided.

classmethod register_backend_callback(backend, callback)

Registers a hook which is run when a backend is loaded

class holoviews.util.opts(*args, **params)

Bases: ParameterizedFunction

Utility function to set options at the global level or to provide an Options object that can be used with the .options method of an element or container.

Option objects can be generated and validated in a tab-completable way (in appropriate environments such as Jupyter notebooks) using completers such as opts.Curve, opts.Image, opts.Overlay, etc.

To set opts globally you can pass these option objects into opts.defaults:

opts.defaults(*options)

For instance:

opts.defaults(opts.Curve(color=’red’))

To set opts on a specific object, you can supply these option objects to the .options method.

For instance:

curve = hv.Curve([1,2,3]) curve.options(opts.Curve(color=’red’))

The options method also accepts lists of Option objects.

strict = param.Boolean(allow_refs=False, default=False, label=’Strict’, nested_refs=False, rx=<param.reactive.reactive_ops object at 0x305a63bd0>)

Whether to be strict about the options specification. If not set to strict (default), any invalid keywords are simply skipped. If strict, invalid keywords prevent the options being applied.

classmethod apply_groups(obj, options=None, backend=None, clone=True, **kwargs)

Applies nested options definition grouped by type.

Applies options on an object or nested group of objects, returning a new object with the options applied. This method accepts the separate option namespaces explicitly (i.e. ‘plot’, ‘style’, and ‘norm’).

If the options are to be set directly on the object a simple format may be used, e.g.:

opts.apply_groups(obj, style={‘cmap’: ‘viridis’},

plot={‘show_title’: False})

If the object is nested the options must be qualified using a type[.group][.label] specification, e.g.:

opts.apply_groups(obj, {‘Image’: {‘plot’: {‘show_title’: False},

‘style’: {‘cmap’: ‘viridis}}})

If no opts are supplied all options on the object will be reset.

Args:

options (dict): Options specification

Options specification should be indexed by type[.group][.label] or option type (‘plot’, ‘style’, ‘norm’).

backend (optional): Backend to apply options to

Defaults to current selected backend

clone (bool, optional): Whether to clone object

Options can be applied inplace with clone=False

**kwargs: Keywords of options by type

Applies options directly to the object by type (e.g. ‘plot’, ‘style’, ‘norm’) specified as dictionaries.

Returns:

Returns the object or a clone with the options applied

classmethod defaults(*options, **kwargs)

Set default options for a session.

Set default options for a session. whether in a Python script or a Jupyter notebook.

Args:

*options: Option objects used to specify the defaults. backend: The plotting extension the options apply to

classmethod instance(**params)

Return an instance of this class, copying parameters from any existing instance provided.

class holoviews.util.output(*args, **params)

Bases: ParameterizedFunction

Helper used to set HoloViews display options. Arguments are supplied as a series of keywords in any order:

backend : The backend used by HoloViews fig : The static figure format holomap : The display type for holomaps widgets : The widget mode for widgets fps : The frames per second used for animations max_frames : The max number of frames rendered (default 500) size : The percentage size of displayed output dpi : The rendered dpi of the figure filename : The filename of the saved output, if any (default None) info : The information to page about the displayed objects (default False) css : Optional css style attributes to apply to the figure image tag widget_location : The position of the widgets relative to the plot

classmethod instance(**params)

Return an instance of this class, copying parameters from any existing instance provided.

holoviews.util.render(obj, backend=None, **kwargs)

Renders the HoloViews object to the corresponding object in the specified backend, e.g. a Matplotlib or Bokeh figure.

The backend defaults to the currently declared default backend. The resulting object can then be used with other objects in the specified backend. For instance, if you want to make a multi-part Bokeh figure using a plot type only available in HoloViews, you can use this function to return a Bokeh figure that you can use like any hand-constructed Bokeh figure in a Bokeh layout.

Arguments

obj: HoloViews object

The HoloViews object to render

backend: string

A valid HoloViews rendering backend

**kwargs: dict

Additional keyword arguments passed to the renderer, e.g. fps for animations

Returns

rendered:

The rendered representation of the HoloViews object, e.g. if backend=’matplotlib’ a matplotlib Figure or FuncAnimation

holoviews.util.renderer(name)

Helper utility to access the active renderer for a given extension.

holoviews.util.save(obj, filename, fmt='auto', backend=None, resources='cdn', toolbar=None, title=None, **kwargs)

Saves the supplied object to file.

The available output formats depend on the backend being used. By default and if the filename is a string the output format will be inferred from the file extension. Otherwise an explicit format will need to be specified. For ambiguous file extensions such as html it may be necessary to specify an explicit fmt to override the default, e.g. in the case of ‘html’ output the widgets will default to fmt=’widgets’, which may be changed to scrubber widgets using fmt=’scrubber’.

Arguments

obj: HoloViews object

The HoloViews object to save to file

filename: string or IO object

The filename or BytesIO/StringIO object to save to

fmt: string

The format to save the object as, e.g. png, svg, html, or gif and if widgets are desired either ‘widgets’ or ‘scrubber’

backend: string

A valid HoloViews rendering backend, e.g. bokeh or matplotlib

resources: string or bokeh.resource.Resources

Bokeh resources used to load bokehJS components. Defaults to CDN, to embed resources inline for offline usage use ‘inline’ or bokeh.resources.INLINE.

toolbar: bool or None

Whether to include toolbars in the exported plot. If None, display the toolbar unless fmt is png and backend is bokeh. If True, always include the toolbar. If False, do not include the toolbar.

title: string

Custom title for exported HTML file

**kwargs: dict

Additional keyword arguments passed to the renderer, e.g. fps for animations

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_versions Module

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command Module

python -m holoviews.util.command Conversion_Example.ipynb OR holoviews Conversion_Example.ipynb

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locator Module

Minimal set of functionality of Matplotlib’s MaxNLocator to choose contour levels without having to have Matplotlib installed. Taken from Matplotlib 3.8.0.

holoviews.util.locator.nonsingular(vmin, vmax, expander=0.001, tiny=1e-15, increasing=True)

Modify the endpoints of a range as needed to avoid singularities.

Parameters

vmin, vmaxfloat

The initial endpoints.

expanderfloat, default: 0.001

Fractional amount by which vmin and vmax are expanded if the original interval is too small, based on tiny.

tinyfloat, default: 1e-15

Threshold for the ratio of the interval to the maximum absolute value of its endpoints. If the interval is smaller than this, it will be expanded. This value should be around 1e-15 or larger; otherwise the interval will be approaching the double precision resolution limit.

increasingbool, default: True

If True, swap vmin, vmax if vmin > vmax.

Returns

vmin, vmaxfloat

Endpoints, expanded and/or swapped if necessary. If either input is inf or NaN, or if both inputs are 0 or very close to zero, it returns -expander, expander.

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parser Module

The magics offered by the HoloViews IPython extension are powerful and support rich, compositional specifications. To avoid the the brittle, convoluted code that results from trying to support the syntax in pure Python, this file defines suitable parsers using pyparsing that are cleaner and easier to understand.

Pyparsing is required by matplotlib and will therefore be available if HoloViews is being used in conjunction with matplotlib.

class holoviews.util.parser.CompositorSpec

Bases: Parser

The syntax for defining a set of compositor is as follows:

[ mode op(spec) [settings] value ]+

The components are:

mode : Operation mode, either ‘data’ or ‘display’. group : Value identifier with capitalized initial letter. op : The name of the operation to apply. spec : Overlay specification of form (A * B) where A and B are

dotted path specifications.

settingsOptional list of keyword arguments to be used as

parameters to the operation (in square brackets).

classmethod collect_tokens(parseresult, mode)

Collect the tokens from a (potentially) nested parse result.

classmethod parse(line, ns=None)

Parse compositor specifications, returning a list Compositors

classmethod todict(parseresult, mode='parens', ns=None)

Helper function to return dictionary given the parse results from a pyparsing.nestedExpr object (containing keywords).

The ns is a dynamic namespace (typically the IPython Notebook namespace) used to update the class-level namespace.

class holoviews.util.parser.OptsSpec

Bases: Parser

An OptsSpec is a string specification that describes an OptionTree. It is a list of tree path specifications (using dotted syntax) separated by keyword lists for any of the style, plotting or normalization options. These keyword lists are denoted ‘plot(..)’, ‘style(…)’ and ‘norm(…)’ respectively. These three groups may be specified even more concisely using keyword lists delimited by square brackets, parentheses and braces respectively. All these sets are optional and may be supplied in any order.

For instance, the following string:

Image (interpolation=None) plot(show_title=False) Curve style(color=’r’)

Would specify an OptionTree where Image has “interpolation=None” for style and ‘show_title=False’ for plot options. The Curve has a style set such that color=’r’.

The parser is fairly forgiving; commas between keywords are optional and additional spaces are often allowed. The only restriction is that keywords must be immediately followed by the ‘=’ sign (no space).

classmethod apply_deprecations(path)

Convert any potentially deprecated paths and issue appropriate warnings

classmethod collect_tokens(parseresult, mode)

Collect the tokens from a (potentially) nested parse result.

classmethod parse(line, ns=None)

Parse an options specification, returning a dictionary with path keys and {‘plot’:<options>, ‘style’:<options>} values.

classmethod parse_options(line, ns=None)

Similar to parse but returns a list of Options objects instead of the dictionary format.

classmethod process_normalization(parse_group)

Given a normalization parse group (i.e. the contents of the braces), validate the option list and compute the appropriate integer value for the normalization plotting option.

classmethod todict(parseresult, mode='parens', ns=None)

Helper function to return dictionary given the parse results from a pyparsing.nestedExpr object (containing keywords).

The ns is a dynamic namespace (typically the IPython Notebook namespace) used to update the class-level namespace.

class holoviews.util.parser.Parser

Bases: object

Base class for magic line parsers, designed for forgiving parsing of keyword lists.

classmethod collect_tokens(parseresult, mode)

Collect the tokens from a (potentially) nested parse result.

classmethod todict(parseresult, mode='parens', ns=None)

Helper function to return dictionary given the parse results from a pyparsing.nestedExpr object (containing keywords).

The ns is a dynamic namespace (typically the IPython Notebook namespace) used to update the class-level namespace.

class holoviews.util.parser.ParserWarning(*, name)

Bases: Parameterized

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settings Module

class holoviews.util.settings.KeywordSettings

Bases: object

Base class for options settings used to specified collections of keyword options.

classmethod extract_keywords(line, items)

Given the keyword string, parse a dictionary of options.

classmethod get_options(items, options, warnfn)

Given a keyword specification, validate and compute options

classmethod update_options(options, items)

Allows updating options depending on class attributes and unvalidated options.

class holoviews.util.settings.OutputSettings

Bases: KeywordSettings

Class for controlling display and output settings.

classmethod extract_keywords(line, items)

Given the keyword string, parse a dictionary of options.

classmethod get_options(items, options, warnfn)

Given a keyword specification, validate and compute options

classmethod update_options(options, items)

Switch default options and backend if new backend is supplied in items.

holoviews.util.settings.list_formats(format_type, backend=None)

Returns list of supported formats for a particular backend.

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transform Module

class holoviews.util.transform.df_dim(obj, *args, **kwargs)

Bases: dim

A subclass of dim which provides access to the DataFrame namespace along with tab-completion and type coercion allowing the expression to be applied on any columnar dataset.

applies(dataset, strict=False)

Determines whether the dim transform can be applied to the Dataset, i.e. whether all referenced dimensions can be resolved.

apply(dataset, flat=False, expanded=None, ranges=None, all_values=False, keep_index=False, compute=True, strict=False)

Evaluates the transform on the supplied dataset.

Args:

dataset: Dataset object to evaluate the expression on flat: Whether to flatten the returned array expanded: Whether to use the expanded expand values ranges: Dictionary for ranges for normalization all_values: Whether to evaluate on all values

Whether to evaluate on all available values, for some element types, such as Graphs, this may include values not included in the referenced column

keep_index: For data types that support indexes, whether the index

should be preserved in the result.

compute: For data types that support lazy evaluation, whether

the result should be computed before it is returned.

strict: Whether to strictly check for dimension matches

(if False, counts any dimensions with matching names as the same)

Returns:

values: NumPy array computed by evaluating the expression

bin(bins, labels=None)

Bins continuous values.

Bins continuous using the provided bins and assigns labels either computed from each bins center point or from the supplied labels.

Args:

bins: List or array containing the bin boundaries labels: List of labels to assign to each bin

If the bins are length N the labels should be length N-1

categorize(categories, default=None)

Replaces discrete values with supplied categories

Replaces discrete values in input array into a fixed set of categories defined either as a list or dictionary.

Args:

categories: List or dict of categories to map inputs to default: Default value to assign if value not in categories

clone(dimension=None, ops=None, dim_type=None)

Creates a clone of the dim expression optionally overriding the dim and ops.

lognorm(limits=None)

Unity-based normalization log scale.

Apply the same transformation as matplotlib.colors.LogNorm

Args:

limits: tuple of (min, max) defining the normalization range

norm(limits=None)

Unity-based normalization to scale data into 0-1 range.

(values - min) / (max - min)

Args:

limits: tuple of (min, max) defining the normalization range

classmethod pipe(func, *args, **kwargs)

Wrapper to give multidimensional transforms a more intuitive syntax. For a custom function ‘func’ with signature (*args, **kwargs), call as dim.pipe(func, *args, **kwargs).

classmethod register(key, function)

Register a custom dim transform function which can from then on be referenced by the key.

property str

Casts values to strings or provides str accessor.

class holoviews.util.transform.dim(obj, *args, **kwargs)

Bases: object

dim transform objects are a way to express deferred transforms on Datasets. dim transforms support all mathematical and bitwise operators, NumPy ufuncs and methods, and provide a number of useful methods for normalizing, binning and categorizing data.

applies(dataset, strict=False)

Determines whether the dim transform can be applied to the Dataset, i.e. whether all referenced dimensions can be resolved.

apply(dataset, flat=False, expanded=None, ranges=None, all_values=False, keep_index=False, compute=True, strict=False)

Evaluates the transform on the supplied dataset.

Args:

dataset: Dataset object to evaluate the expression on flat: Whether to flatten the returned array expanded: Whether to use the expanded expand values ranges: Dictionary for ranges for normalization all_values: Whether to evaluate on all values

Whether to evaluate on all available values, for some element types, such as Graphs, this may include values not included in the referenced column

keep_index: For data types that support indexes, whether the index

should be preserved in the result.

compute: For data types that support lazy evaluation, whether

the result should be computed before it is returned.

strict: Whether to strictly check for dimension matches

(if False, counts any dimensions with matching names as the same)

Returns:

values: NumPy array computed by evaluating the expression

bin(bins, labels=None)

Bins continuous values.

Bins continuous using the provided bins and assigns labels either computed from each bins center point or from the supplied labels.

Args:

bins: List or array containing the bin boundaries labels: List of labels to assign to each bin

If the bins are length N the labels should be length N-1

categorize(categories, default=None)

Replaces discrete values with supplied categories

Replaces discrete values in input array into a fixed set of categories defined either as a list or dictionary.

Args:

categories: List or dict of categories to map inputs to default: Default value to assign if value not in categories

clone(dimension=None, ops=None, dim_type=None)

Creates a clone of the dim expression optionally overriding the dim and ops.

lognorm(limits=None)

Unity-based normalization log scale.

Apply the same transformation as matplotlib.colors.LogNorm

Args:

limits: tuple of (min, max) defining the normalization range

norm(limits=None)

Unity-based normalization to scale data into 0-1 range.

(values - min) / (max - min)

Args:

limits: tuple of (min, max) defining the normalization range

classmethod pipe(func, *args, **kwargs)

Wrapper to give multidimensional transforms a more intuitive syntax. For a custom function ‘func’ with signature (*args, **kwargs), call as dim.pipe(func, *args, **kwargs).

classmethod register(key, function)

Register a custom dim transform function which can from then on be referenced by the key.

property str

Casts values to strings or provides str accessor.

holoviews.util.transform.easting_northing_to_lon_lat(easting, northing)

Projects the given easting, northing values into longitude, latitude coordinates.

easting and northing values are assumed to be in Web Mercator (aka Pseudo-Mercator or EPSG:3857) coordinates.

Args:

easting northing

Returns:

(longitude, latitude)

class holoviews.util.transform.iloc(dim_expr)

Bases: object

Implements integer array indexing for dim expressions.

class holoviews.util.transform.loc(dim_expr)

Bases: object

Implements loc for dim expressions.

holoviews.util.transform.lognorm(values, min=None, max=None)

Unity-based normalization on log scale.

Apply the same transformation as matplotlib.colors.LogNorm

Args:

values: Array of values to be normalized min (float, optional): Lower bound of normalization range max (float, optional): Upper bound of normalization range

Returns:

Array of normalized values

holoviews.util.transform.lon_lat_to_easting_northing(longitude, latitude)

Projects the given longitude, latitude values into Web Mercator (aka Pseudo-Mercator or EPSG:3857) coordinates.

Longitude and latitude can be provided as scalars, Pandas columns, or Numpy arrays, and will be returned in the same form. Lists or tuples will be converted to Numpy arrays.

Args:

longitude latitude

Returns:

(easting, northing)

Examples:

easting, northing = lon_lat_to_easting_northing(-74,40.71)

easting, northing = lon_lat_to_easting_northing(

np.array([-74]),np.array([40.71])

)

df=pandas.DataFrame(dict(longitude=np.array([-74]),latitude=np.array([40.71]))) df.loc[:, ‘longitude’], df.loc[:, ‘latitude’] = lon_lat_to_easting_northing(

df.longitude,df.latitude

)

holoviews.util.transform.norm(values, min=None, max=None)

Unity-based normalization to scale data into 0-1 range.

(values - min) / (max - min)

Args:

values: Array of values to be normalized min (float, optional): Lower bound of normalization range max (float, optional): Upper bound of normalization range

Returns:

Array of normalized values

class holoviews.util.transform.xr_dim(obj, *args, **kwargs)

Bases: dim

A subclass of dim which provides access to the xarray DataArray namespace along with tab-completion and type coercion allowing the expression to be applied on any gridded dataset.

applies(dataset, strict=False)

Determines whether the dim transform can be applied to the Dataset, i.e. whether all referenced dimensions can be resolved.

apply(dataset, flat=False, expanded=None, ranges=None, all_values=False, keep_index=False, compute=True, strict=False)

Evaluates the transform on the supplied dataset.

Args:

dataset: Dataset object to evaluate the expression on flat: Whether to flatten the returned array expanded: Whether to use the expanded expand values ranges: Dictionary for ranges for normalization all_values: Whether to evaluate on all values

Whether to evaluate on all available values, for some element types, such as Graphs, this may include values not included in the referenced column

keep_index: For data types that support indexes, whether the index

should be preserved in the result.

compute: For data types that support lazy evaluation, whether

the result should be computed before it is returned.

strict: Whether to strictly check for dimension matches

(if False, counts any dimensions with matching names as the same)

Returns:

values: NumPy array computed by evaluating the expression

bin(bins, labels=None)

Bins continuous values.

Bins continuous using the provided bins and assigns labels either computed from each bins center point or from the supplied labels.

Args:

bins: List or array containing the bin boundaries labels: List of labels to assign to each bin

If the bins are length N the labels should be length N-1

categorize(categories, default=None)

Replaces discrete values with supplied categories

Replaces discrete values in input array into a fixed set of categories defined either as a list or dictionary.

Args:

categories: List or dict of categories to map inputs to default: Default value to assign if value not in categories

clone(dimension=None, ops=None, dim_type=None)

Creates a clone of the dim expression optionally overriding the dim and ops.

lognorm(limits=None)

Unity-based normalization log scale.

Apply the same transformation as matplotlib.colors.LogNorm

Args:

limits: tuple of (min, max) defining the normalization range

norm(limits=None)

Unity-based normalization to scale data into 0-1 range.

(values - min) / (max - min)

Args:

limits: tuple of (min, max) defining the normalization range

classmethod pipe(func, *args, **kwargs)

Wrapper to give multidimensional transforms a more intuitive syntax. For a custom function ‘func’ with signature (*args, **kwargs), call as dim.pipe(func, *args, **kwargs).

classmethod register(key, function)

Register a custom dim transform function which can from then on be referenced by the key.

property str

Casts values to strings or provides str accessor.

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warnings Module

exception holoviews.util.warnings.HoloviewsDeprecationWarning

Bases: DeprecationWarning

A Holoviews-specific DeprecationWarning subclass. Used to selectively filter Holoviews deprecations for unconditional display.

add_note()

Exception.add_note(note) – add a note to the exception

with_traceback()

Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception holoviews.util.warnings.HoloviewsUserWarning

Bases: UserWarning

A Holoviews-specific UserWarning subclass. Used to selectively filter Holoviews warnings for unconditional display.

add_note()

Exception.add_note(note) – add a note to the exception

with_traceback()

Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

holoviews.util.warnings.find_stack_level()

Find the first place in the stack that is not inside Holoviews and Param. Inspired by: pandas.util._exceptions.find_stack_level

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