brushedPoints: Find rows of data selected on an interactive plot.

In rstudio/shiny: Web Application Framework for R

Find rows of data selected on an interactive plot.

Description

brushedPoints() returns rows from a data frame which are under a brush. nearPoints() returns rows from a data frame which are near a click, hover, or double-click. Alternatively, set allRows = TRUE to return all rows from the input data with an additional column selected_ that indicates which rows of the would be selected.

Usage

brushedPoints(
  df,
  brush,
  xvar = NULL,
  yvar = NULL,
  panelvar1 = NULL,
  panelvar2 = NULL,
  allRows = FALSE
)

nearPoints(
  df,
  coordinfo,
  xvar = NULL,
  yvar = NULL,
  panelvar1 = NULL,
  panelvar2 = NULL,
  threshold = 5,
  maxpoints = NULL,
  addDist = FALSE,
  allRows = FALSE
)

Arguments

df	A data frame from which to select rows.
brush, coordinfo	The data from a brush or click/dblclick/hover event e.g. input$plot_brush, input$plot_click.
xvar, yvar	A string giving the name of the variable on the x or y axis. These are only required for base graphics, and must be the name of a column in df.
panelvar1, panelvar2	A string giving the name of a panel variable. For expert use only; in most cases these will be automatically derived from the ggplot2 spec.
allRows	If FALSE (the default) return a data frame containing the selected rows. If TRUE, the input data frame will have a new column, selected_, which indicates whether the row was selected or not.
threshold	A maximum distance (in pixels) to the pointer location. Rows in the data frame will be selected if the distance to the pointer is less than threshold.
maxpoints	Maximum number of rows to return. If NULL (the default), will return all rows within the threshold distance.
addDist	If TRUE, add a column named dist_ that contains the distance from the coordinate to the point, in pixels. When no pointer event has yet occurred, the value of dist_ will be NA.

Value

A data frame based on df, containing the observations selected by the brush or near the click event. For nearPoints(), the rows will be sorted by distance to the event.

If allRows = TRUE, then all rows will returned, along with a new selected_ column that indicates whether or not the point was selected. The output from nearPoints() will no longer be sorted, but you can set addDist = TRUE to get an additional column that gives the pixel distance to the pointer.

ggplot2

For plots created with ggplot2, it is not necessary to specify the column names to xvar, yvar, panelvar1, and panelvar2 as that information can be automatically derived from the plot specification.

Note, however, that this will not work if you use a computed column, like ⁠aes(speed/2, dist))⁠. Instead, we recommend that you modify the data first, and then make the plot with "raw" columns in the modified data.

Brushing

If x or y column is a factor, then it will be coerced to an integer vector. If it is a character vector, then it will be coerced to a factor and then integer vector. This means that the brush will be considered to cover a given character/factor value when it covers the center value.

If the brush is operating in just the x or y directions (e.g., with brushOpts(direction = "x"), then this function will filter out points using just the x or y variable, whichever is appropriate.

See Also

plotOutput() for example usage.

Examples

## Not run: 
# Note that in practice, these examples would need to go in reactives
# or observers.

# This would select all points within 5 pixels of the click
nearPoints(mtcars, input$plot_click)

# Select just the nearest point within 10 pixels of the click
nearPoints(mtcars, input$plot_click, threshold = 10, maxpoints = 1)


## End(Not run)

rstudio/shiny documentation built on Nov. 8, 2024, 6 a.m.