Find rows of data that are near a click/hover/double-click — nearPoints

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.
coordinfo	The data from a mouse event, such as input$plot_click.
xvar	A string with the name of the variable on the x or y axis. This must also be the name of a column in df. If absent, then this function will try to infer the variable from the brush (only works for ggplot2).
yvar	A string with the name of the variable on the x or y axis. This must also be the name of a column in df. If absent, then this function will try to infer the variable from the brush (only works for ggplot2).
panelvar1	Each of these is a string with the name of a panel variable. For example, if with ggplot2, you facet on a variable called cyl, then you can use "cyl" here. However, specifying the panel variable should not be necessary with ggplot2; Shiny should be able to auto-detect the panel variable.
panelvar2	Each of these is a string with the name of a panel variable. For example, if with ggplot2, you facet on a variable called cyl, then you can use "cyl" here. However, specifying the panel variable should not be necessary with ggplot2; Shiny should be able to auto-detect the panel variable.
threshold	A maxmimum distance to the click point; rows in the data frame where the distance to the click is less than threshold will be returned.
maxpoints	Maximum number of rows to return. If NULL (the default), return all rows that are 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 mouse event has yet occured, the value of dist_ will be NA.
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 inside the selected by the mouse event (TRUE) or not (FALSE).

Description

This function returns rows from a data frame which are near a click, hover, or double-click, when used with plotOutput(). The rows will be sorted by their distance to the mouse event.

Details

It is also possible for this function to return all rows from the input data frame, but with an additional column selected_, which indicates which rows of the input data frame are selected by the brush (TRUE for selected, FALSE for not-selected). This is enabled by setting allRows=TRUE option. If this is used, the resulting data frame will not be sorted by distance to the mouse event.

The xvar, yvar, panelvar1, and panelvar2 arguments specify which columns in the data correspond to the x variable, y variable, and panel variables of the plot. For example, if your plot is plot(x=cars$speed, y=cars$dist), and your click variable is named "cars_click", then you would use nearPoints(cars, input$cars_brush, "speed", "dist").

See also

plotOutput() for more examples.

Examples

if (FALSE) {
# 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)

}