bokeh.models.tools¶

Bokeh comes with a number of interactive tools.

There are five types of tool interactions:

For the first three comprise the category of gesture tools, and only one tool for each gesture can be active at any given time. The active tool is indicated on the toolbar by a highlight next to to the tool. Actions are immediate or modal operations that are only activated when their button in the toolbar is pressed. Inspectors are passive tools that merely report information or annotate the plot in some way, and may always be active regardless of what other tools are currently active.

class Action(**kwargs)¶

Bases: bokeh.models.tools.Tool

{
  "id": "742bf865-3271-4e0f-87a8-0c78b3e1b681",
  "name": null,
  "plot": null,
  "tags": []
}

class BoxSelectTool(**kwargs)¶

Bases: bokeh.models.tools.Drag

toolbar icon:

The box selection tool allows users to make selections on a Plot by indicating a rectangular region by dragging the mouse or a finger over the plot region. The end of the drag event indicates the selection region is ready.

See Selected and Unselected Glyphs for information on styling selected and unselected glyphs.

callback¶

property type: callback:Instance(Callback)

A callback to run in the browser on completion of drawing a selection box. The cb_data parameter that is available to the Callback code will contain one BoxSelectTool-specific field:

Geometry:	object containing the coordinates of the selection box

dimensions¶

property type: dimensions:Enum(‘width’, ‘height’, ‘both’)

Which dimensions the box selection is to be free in. By default, users may freely draw selections boxes with any dimensions. If only “width” is supplied, the box will be constrained to span the entire vertical space of the plot, only the horizontal dimension can be controlled. If only “height” is supplied, the box will be constrained to span the entire horizontal space of the plot, and the vertical dimension can be controlled.

names¶

property type: names:List(String)

A list of names to query for. If set, only renderers that have a matching value for their name attribute will be used.

overlay¶

property type: overlay:Instance(BoxAnnotation)

A shaded annotation drawn to indicate the selection region.

renderers¶

property type: renderers:List(Instance(Renderer))

An explicit list of renderers to hit test again. If unset, defaults to all renderers on a plot.

select_every_mousemove¶

property type: select_every_mousemove:Bool

Whether a selection computation should happen on every mouse event, or only once, when the selection region is completed. Default: False

{
  "callback": null,
  "dimensions": "both",
  "id": "b923a6d5-fd40-46f6-bd24-41202cda8fad",
  "name": null,
  "names": [],
  "overlay": {
    "id": "a0c7bada-278a-4922-bf1d-2af1a9bca7ec",
    "type": "BoxAnnotation"
  },
  "plot": null,
  "renderers": [],
  "select_every_mousemove": false,
  "tags": []
}

class BoxZoomTool(**kwargs)¶

Bases: bokeh.models.tools.Drag

toolbar icon:

The box zoom tool allows users to define a rectangular region of a Plot to zoom to by dragging he mouse or a finger over the plot region. The end of the drag event indicates the selection region is ready.

dimensions¶

property type: dimensions:Enum(‘width’, ‘height’, ‘both’)

Which dimensions the zoom box is to be free in. By default, users may freely draw zoom boxes with any dimensions. If only “width” is supplied, the box will be constrained to span the entire vertical space of the plot, only the horizontal dimension can be controlled. If only “height” is supplied, the box will be constrained to span the entire horizontal space of the plot, and the vertical dimension can be controlled.

match_aspect¶

property type: match_aspect:Bool

Whether the box zoom region should be restricted to have the same aspect ratio as the plot region.

Note

If the tool is restricted to one dimension, this value has no effect.

overlay¶

property type: overlay:Instance(BoxAnnotation)

A shaded annotation drawn to indicate the selection region.

{
  "dimensions": "both",
  "id": "b718cdde-c624-4f46-842c-8a7bae8d69e5",
  "match_aspect": false,
  "name": null,
  "overlay": {
    "id": "6235972a-d295-4273-98df-d19b47565f54",
    "type": "BoxAnnotation"
  },
  "plot": null,
  "tags": []
}

class CrosshairTool(**kwargs)¶

Bases: bokeh.models.tools.Inspection

toolbar icon:

The crosshair tool is a passive inspector tool. It is generally on at all times, but can be configured in the inspector’s menu associated with the toolbar icon shown above.

The crosshair tool draws a crosshair annotation over the plot, centered on the current mouse position. The crosshair tool may be configured to draw across only one dimension by setting the dimension property to only width or height.

dimensions¶

property type: dimensions:Enum(‘width’, ‘height’, ‘both’)

Which dimensions the crosshair tool is to track. By default, both a vertical and horizontal line will be drawn. If only “width” is supplied, only a horizontal line will be drawn. If only “height” is supplied, only a vertical line will be drawn.

line_alpha¶

property type: line_alpha:Float

An alpha value to use to stroke paths with.

Acceptable values are floating point numbers between 0 (transparent) and 1 (opaque).

line_color¶

property type: line_color:Color

A color to use to stroke paths with.

Acceptable values are:

• any of the 147 named CSS colors, e.g 'green', 'indigo'
• an RGB(A) hex value, e.g., '#FF0000', '#44444444'
• a 3-tuple of integers (r,g,b) between 0 and 255
• a 4-tuple of (r,g,b,a) where r,g,b are integers between 0..255 and a is between 0..1

line_width¶

property type: line_width:Float

Stroke width in units of pixels.

{
  "dimensions": "both",
  "id": "007e10e6-aa35-46eb-bd17-e389fce0f43c",
  "line_alpha": 1.0,
  "line_color": "black",
  "line_width": 1,
  "name": null,
  "plot": null,
  "tags": []
}

class Drag(**kwargs)¶

Bases: bokeh.models.tools.Tool

{
  "id": "a43e8868-e0ff-41c6-8eff-c196a1387baf",
  "name": null,
  "plot": null,
  "tags": []
}

class HelpTool(**kwargs)¶

Bases: bokeh.models.tools.Action

The help tool is a widget designed to replace the hardcoded ‘Help’ link. The hover text can be customized through the help_tooltip attribute and the redirect site overridden as well.

help_tooltip¶

property type: help_tooltip:String

Tooltip displayed when hovering over the help icon.

redirect¶

property type: redirect:String

Site to be redirected through upon click.

{
  "help_tooltip": "Click the question mark to learn more about Bokeh plot tools.",
  "id": "aaf86793-4669-4c24-8bba-ae5aed9f6039",
  "name": null,
  "plot": null,
  "redirect": "http://bokeh.pydata.org/en/latest/docs/user_guide/tools.html",
  "tags": []
}

class HoverTool(**kwargs)¶

Bases: bokeh.models.tools.Inspection

toolbar icon:

The hover tool is a passive inspector tool. It is generally on at all times, but can be configured in the inspector’s menu associated with the toolbar icon shown above.

By default, the hover tool displays informational tooltips whenever the cursor is directly over a glyph. The data to show comes from the glyph’s data source, and what is to be displayed is configurable with the tooltips attribute that maps display names to columns in the data source, or to special known variables.

Here is an example of how to configure and use the hover tool:

# Add tooltip (name, field) pairs to the tool. See below for a
# description of possible field values.
hover.tooltips = [
    ("index", "$index"),
    ("(x,y)", "($x, $y)"),
    ("radius", "@radius"),
    ("fill color", "$color[hex, swatch]:fill_color"),
    ("foo", "@foo"),
    ("bar", "@bar"),
]

You can also supply a Callback to the HoverTool, to build custom interactions on hover. In this case you may want to turn the tooltips off by setting tooltips=None.

Warning

Hover tool does not currently work with the following glyphs:

annulus arc bezier image image_rgba

image_url multi_line oval patch

quadratic ray segment text

anchor¶

property type: anchor:Enum(‘top_left’, ‘top_center’, ‘top_right’, ‘right_center’, ‘bottom_right’, ‘bottom_center’, ‘bottom_left’, ‘left_center’, ‘center’)

If point policy is set to “snap_to_data”, anchor defines the attachment point of a tooltip. The default is to attach to the center of a glyph.

attachment¶

property type: attachment:Enum(‘horizontal’, ‘vertical’)

Whether tooltip’s arrow should appear in the horizontal or vertical dimension.

callback¶

property type: callback:Instance(Callback)

A callback to run in the browser whenever the input’s value changes. The cb_data parameter that is available to the Callback code will contain two HoverTool specific fields:

Index:	object containing the indices of the hovered points in the data source
Geometry:	object containing the coordinates of the hover cursor

line_policy¶

property type: line_policy:Enum(‘prev’, ‘next’, ‘nearest’, ‘interp’, ‘none’)

When showing tooltips for lines, whether the tooltip position should be the “previous” or “next” points on the line, the nearest point to the current mouse position, or interpolate along the line to the current mouse position.

mode¶

property type: mode:Enum(‘mouse’, ‘hline’, ‘vline’)

Whether to consider hover pointer as a point (x/y values), or a span on h or v directions.

names¶

property type: names:List(String)

A list of names to query for. If set, only renderers that have a matching value for their name attribute will be used.

point_policy¶

property type: point_policy:Enum(‘snap_to_data’, ‘follow_mouse’, ‘none’)

Whether the tooltip position should snap to the “center” (or other anchor) position of the associated glyph, or always follow the current mouse cursor position.

renderers¶

property type: renderers:List(Instance(Renderer))

An explicit list of renderers to hit test again. If unset, defaults to all renderers on a plot.

show_arrow¶

property type: show_arrow:Bool

Whether tooltip’s arrow should be showed.

tooltips¶

property type: tooltips:Either(String, List(Tuple(String, String)))

The (name, field) pairs describing what the hover tool should display when there is a hit.

Field names starting with “@” are interpreted as columns on the data source. For instance, “@temp” would look up values to display from the “temp” column of the data source.

Field names starting with “$” are special, known fields:

$index:	index of selected point in the data source
$x:	x-coordinate under the cursor in data space
$y:	y-coordinate under the cursor in data space
$sx:	x-coordinate under the cursor in screen (canvas) space
$sy:	y-coordinate under the cursor in screen (canvas) space
$color:	color data from data source, with the syntax: $color[options]:field_name. The available options are: ‘hex’ (to display the color as a hex value), and ‘swatch’ to also display a small color swatch.

None is also a valid value for tooltips. This turns off the rendering of tooltips. This is mostly useful when supplying other actions on hover via the callback property.

Note

The tooltips attribute can also be configured with a mapping type, e.g. dict or OrderedDict. However, if a dict is used, the visual presentation order is unspecified.

{
  "anchor": "center",
  "attachment": "horizontal",
  "callback": null,
  "id": "4ab65fc0-bd04-4f78-bc5a-e03f6a9a1866",
  "line_policy": "prev",
  "mode": "mouse",
  "name": null,
  "names": [],
  "plot": null,
  "point_policy": "snap_to_data",
  "renderers": [],
  "show_arrow": true,
  "tags": [],
  "tooltips": [
    [
      "index",
      "$index"
    ],
    [
      "data (x, y)",
      "($x, $y)"
    ],
    [
      "canvas (x, y)",
      "($sx, $sy)"
    ]
  ]
}

class Inspection(**kwargs)¶

Bases: bokeh.models.tools.Tool

{
  "id": "13463329-7db1-4b6b-8004-c9b05c8c1acb",
  "name": null,
  "plot": null,
  "tags": []
}

class LassoSelectTool(**kwargs)¶

Bases: bokeh.models.tools.Drag

toolbar icon:

The lasso selection tool allows users to make selections on a Plot by indicating a free-drawn “lasso” region by dragging the mouse or a finger over the plot region. The end of the drag event indicates the selection region is ready.

See Selected and Unselected Glyphs for information on styling selected and unselected glyphs.

Note

Selections can be comprised of multiple regions, even those made by different selection tools. Hold down the <<shift>> key while making a selection to append the new selection to any previous selection that might exist.

callback¶

property type: callback:Instance(Callback)

A callback to run in the browser on every selection of a lasso area. The cb_data parameter that is available to the Callback code will contain one LassoSelectTool-specific field:

Geometry:	object containing the coordinates of the lasso area

names¶

property type: names:List(String)

A list of names to query for. If set, only renderers that have a matching value for their name attribute will be used.

overlay¶

property type: overlay:Instance(PolyAnnotation)

A shaded annotation drawn to indicate the selection region.

renderers¶

property type: renderers:List(Instance(Renderer))

An explicit list of renderers to hit test again. If unset, defaults to all renderers on a plot.

select_every_mousemove¶

property type: select_every_mousemove:Bool

Whether a selection computation should happen on every mouse event, or only once, when the selection region is completed. Default: True

{
  "callback": null,
  "id": "a6bfa3e2-5456-43d1-826c-b6e7f1ad9c6b",
  "name": null,
  "names": [],
  "overlay": {
    "id": "228eaf75-0d7f-4390-873f-597f78d54f27",
    "type": "PolyAnnotation"
  },
  "plot": null,
  "renderers": [],
  "select_every_mousemove": true,
  "tags": []
}

class PanTool(**kwargs)¶

Bases: bokeh.models.tools.Drag

toolbar icon:

The pan tool allows the user to pan a Plot by left-dragging a mouse, or on touch devices by dragging a finger or stylus, across the plot region.

The pan tool also activates the border regions of a Plot for “single axis” panning. For instance, dragging in the vertical border or axis will effect a pan in the vertical direction only, with the horizontal dimension kept fixed.

dimensions¶

property type: dimensions:Enum(‘width’, ‘height’, ‘both’)

Which dimensions the pan tool is constrained to act in. By default the pan tool will pan in any dimension, but can be configured to only pan horizontally across the width of the plot, or vertically across the height of the plot.

{
  "dimensions": "both",
  "id": "f0572d22-a1a6-4b11-9429-e005bbc3cdcf",
  "name": null,
  "plot": null,
  "tags": []
}

class PolySelectTool(**kwargs)¶

Bases: bokeh.models.tools.Tap

toolbar icon:

The polygon selection tool allows users to make selections on a Plot by indicating a polygonal region with mouse clicks. single clicks (or taps) add successive points to the definition of the polygon, and a double click (or tap) indicates the selection region is ready.

See Selected and Unselected Glyphs for information on styling selected and unselected glyphs.

Note

Selections can be comprised of multiple regions, even those made by different selection tools. Hold down the <<shift>> key while making a selection to append the new selection to any previous selection that might exist.

names¶

property type: names:List(String)

A list of names to query for. If set, only renderers that have a matching value for their name attribute will be used.

overlay¶

property type: overlay:Instance(PolyAnnotation)

A shaded annotation drawn to indicate the selection region.

renderers¶

property type: renderers:List(Instance(Renderer))

An explicit list of renderers to hit test again. If unset, defaults to all renderers on a plot.

{
  "id": "cfa681da-a629-4176-93ff-f5bba47c9458",
  "name": null,
  "names": [],
  "overlay": {
    "id": "35277365-739f-4354-b467-8d57f3a3ebf9",
    "type": "PolyAnnotation"
  },
  "plot": null,
  "renderers": [],
  "tags": []
}

class RedoTool(**kwargs)¶

Bases: bokeh.models.tools.Action

toolbar icon:

Redo tool reverses the last action performed by undo tool.

{
  "id": "b883ebf8-0193-4db1-ae71-5899b30237b7",
  "name": null,
  "plot": null,
  "tags": []
}

class ResetTool(**kwargs)¶

Bases: bokeh.models.tools.Action

toolbar icon:

The reset tool is an action. When activated in the toolbar, the tool resets the data bounds of the plot to their values when the plot was initially created.

Optionally, the reset tool also resets the plat canvas dimensions to their original size

reset_size¶

property type: reset_size:Bool

Whether activating the Reset tool should also reset the plot’s canvas dimensions to their original size.

{
  "id": "a8fe050a-1330-4ea1-b30b-a4af973cce8d",
  "name": null,
  "plot": null,
  "reset_size": true,
  "tags": []
}

class ResizeTool(**kwargs)¶

Bases: bokeh.models.tools.Drag

toolbar icon:

The resize tool allows the user to left-drag a mouse or drag a finger to resize the entire plot area on the screen.

{
  "id": "6a8407d8-f7a1-4a3a-91de-23b8e618dd0e",
  "name": null,
  "plot": null,
  "tags": []
}

class SaveTool(**kwargs)¶

Bases: bokeh.models.tools.Action

toolbar icon:

The save tool is an action. When activated, the tool opens a download dialog which allows to save an image reproduction of the plot in PNG format. If automatic download is not support by a web browser, the tool falls back to opening the generated image in a new tab or window. User then can manually save it by right clicking on the image and choosing “Save As” (or similar) menu item.

{
  "id": "d534cfab-6fc3-428a-98de-ac61cfbafc2d",
  "name": null,
  "plot": null,
  "tags": []
}

class Scroll(**kwargs)¶

Bases: bokeh.models.tools.Tool

{
  "id": "839a2c2a-29f1-4efa-93c0-348812de7801",
  "name": null,
  "plot": null,
  "tags": []
}

class Tap(**kwargs)¶

Bases: bokeh.models.tools.Tool

{
  "id": "5704f5d1-3c66-4414-9619-5c30b30f6898",
  "name": null,
  "plot": null,
  "tags": []
}

class TapTool(**kwargs)¶

Bases: bokeh.models.tools.Tap

toolbar icon:

The tap selection tool allows the user to select at single points by left-clicking a mouse, or tapping with a finger.

See Selected and Unselected Glyphs for information on styling selected and unselected glyphs.

Note

Selections can be comprised of multiple regions, even those made by different selection tools. Hold down the <<shift>> key while making a selection to append the new selection to any previous selection that might exist.

behavior¶

property type: behavior:Enum(‘select’, ‘inspect’)

This tool can be configured to either make selections or inspections on associated data sources. The difference is that selection changes propagate across bokeh and other components (e.g. selection glyph) will be notified. Inspecions don’t act like this, so it’s useful to configure callback when setting behavior=’inspect’.

callback¶

property type: callback:Instance(Callback)

A client-side action specification, like opening a URL, showing a dialog box, etc. See Action for details.

names¶

property type: names:List(String)

A list of names to query for. If set, only renderers that have a matching value for their name attribute will be used.

renderers¶

property type: renderers:List(Instance(Renderer))

An explicit list of renderers to hit test again. If unset, defaults to all renderers on a plot.

{
  "behavior": "select",
  "callback": null,
  "id": "76992d69-354d-470a-a737-0549da057732",
  "name": null,
  "names": [],
  "plot": null,
  "renderers": [],
  "tags": []
}

class Tool(**kwargs)¶

Bases: bokeh.model.Model

A base class for all interactive tool types. Tool is not generally useful to instantiate on its own.

plot¶

property type: plot:Instance(Plot)

The Plot that this tool will act on.

{
  "id": "2948545b-f383-44bf-a38c-f42b0c2b07aa",
  "name": null,
  "plot": null,
  "tags": []
}

class ToolEvents(**kwargs)¶

Bases: bokeh.model.Model

geometries¶

property type: geometries:List(Dict(String, Any))

{
  "geometries": [],
  "id": "13777cb7-a6bf-467a-b7af-e5bcd197e42a",
  "name": null,
  "tags": []
}

class Toolbar(**kwargs)¶

Bases: bokeh.models.tools.ToolbarBase

Hold tools to display for a single plot.

active_drag¶

property type: active_drag:Either(Auto, Instance(Drag))

Specify a drag tool to be active when the plot is displayed.

active_scroll¶

property type: active_scroll:Either(Auto, Instance(Scroll))

Specify a scroll/pinch tool to be active when the plot is displayed.

active_tap¶

property type: active_tap:Either(Auto, Instance(Tap))

Specify a tap/click tool to be active when the plot is displayed.

{
  "active_drag": "auto",
  "active_scroll": "auto",
  "active_tap": "auto",
  "disabled": false,
  "height": null,
  "id": "385293ee-440f-451c-91c0-11d36a7a557d",
  "logo": "normal",
  "name": null,
  "sizing_mode": null,
  "tags": [],
  "tools": [],
  "width": null
}

class ToolbarBase(**kwargs)¶

Bases: bokeh.models.layouts.LayoutDOM

A base class for different toolbars. ToolbarBase is not generally useful to instantiate on its own.

logo¶

property type: logo:Enum(‘normal’, ‘grey’)

What version of the Bokeh logo to display on the toolbar. If set to None, no logo will be displayed.

tools¶

property type: tools:List(Instance(Tool))

A list of tools to add to the plot.

{
  "disabled": false,
  "height": null,
  "id": "37ea5f4f-7dac-4b24-a537-fa1f00c3bc4b",
  "logo": "normal",
  "name": null,
  "sizing_mode": null,
  "tags": [],
  "tools": [],
  "width": null
}

class ToolbarBox(*args, **kwargs)¶

Bases: bokeh.models.layouts.Box

A layoutable toolbar that can accept the tools of multiple plots, and can merge the tools into a single button for convenience.

logo¶

property type: logo:Enum(‘normal’, ‘grey’)

What version of the Bokeh logo to display on the toolbar. If set to None, no logo will be displayed.

merge_tools¶

property type: merge_tools:Bool

Merge all the tools together so there is one tool to control all the plots.

toolbar_location¶

property type: toolbar_location:Enum(‘above’, ‘below’, ‘left’, ‘right’)

Should the toolbar be presented as if it was stuck to the above, right, left, below edge of a plot. Default is right.

tools¶

property type: tools:List(Instance(Tool))

A list of tools to add to the plot.

{
  "children": [],
  "disabled": false,
  "height": null,
  "id": "49c2359f-6fb3-4ffd-9cc5-4877f1b1e6a0",
  "logo": "normal",
  "merge_tools": true,
  "name": null,
  "sizing_mode": "fixed",
  "tags": [],
  "toolbar_location": "right",
  "tools": [],
  "width": null
}

class UndoTool(**kwargs)¶

Bases: bokeh.models.tools.Action

toolbar icon:

Undo tool allows to restore previous state of the plot.

{
  "id": "c0da388e-aff3-46b9-94de-7b2ac452d4fc",
  "name": null,
  "plot": null,
  "tags": []
}

class WheelPanTool(**kwargs)¶

Bases: bokeh.models.tools.Scroll

toolbar icon:

The wheel pan tool allows the user to pan the plot along the configured dimension using the scroll wheel.

dimension¶

property type: dimension:Enum(‘width’, ‘height’)

Which dimension the wheel pan tool is constrained to act in. By default the wheel pan tool will pan the plot along the x-axis.

{
  "dimension": "width",
  "id": "5d8a09e9-9a33-4305-8e27-e562e9b5b7a7",
  "name": null,
  "plot": null,
  "tags": []
}

class WheelZoomTool(**kwargs)¶

Bases: bokeh.models.tools.Scroll

toolbar icon:

The wheel zoom tool will zoom the plot in and out, centered on the current mouse location.

The wheel zoom tool also activates the border regions of a Plot for “single axis” zooming. For instance, zooming in the vertical border or axis will effect a zoom in the vertical direction only, with the horizontal dimension kept fixed.

dimensions¶

property type: dimensions:Enum(‘width’, ‘height’, ‘both’)

Which dimensions the wheel zoom tool is constrained to act in. By default the wheel zoom tool will zoom in any dimension, but can be configured to only zoom horizontally across the width of the plot, or vertically across the height of the plot.

{
  "dimensions": "both",
  "id": "d501db22-453d-4e37-bba7-db8ef641d24b",
  "name": null,
  "plot": null,
  "tags": []
}

class ZoomInTool(**kwargs)¶

Bases: bokeh.models.tools.Action

toolbar icon:

The zoom-in tool allows users to click a button to zoom in by a fixed amount.

dimensions¶

property type: dimensions:Enum(‘width’, ‘height’, ‘both’)

Which dimensions the zoom-in tool is constrained to act in. By default the zoom-in zoom tool will zoom in any dimension, but can be configured to only zoom horizontally across the width of the plot, or vertically across the height of the plot.

factor¶

property type: factor:Percent

Percentage to zoom for each click of the zoom-in tool.

{
  "dimensions": "both",
  "factor": 0.1,
  "id": "7660bed6-adaa-4ce6-8252-f14db6a8cd5b",
  "name": null,
  "plot": null,
  "tags": []
}

class ZoomOutTool(**kwargs)¶

Bases: bokeh.models.tools.Action

toolbar icon:

The zoom-out tool allows users to click a button to zoom out by a fixed amount.

dimensions¶

property type: dimensions:Enum(‘width’, ‘height’, ‘both’)

Which dimensions the zoom-out tool is constrained to act in. By default the zoom-out tool will zoom in any dimension, but can be configured to only zoom horizontally across the width of the plot, or vertically across the height of the plot.

factor¶

property type: factor:Percent

Percentage to zoom for each click of the zoom-in tool.

{
  "dimensions": "both",
  "factor": 0.1,
  "id": "e95aa993-5664-4e59-8c11-1cadd3c9c66d",
  "name": null,
  "plot": null,
  "tags": []
}

DEFAULT_BOX_OVERLAY()¶

DEFAULT_POLY_OVERLAY()¶