scale_ordinal: Add a ordinal, nominal, or logical scale to a ggvis object.

Description

Ordinal, nominal, and logical scales are all categorical, and are treated similarly by ggvis.

Usage

scale_ordinal(vis, property, domain = NULL, range = NULL, reverse = NULL,
  round = NULL, points = NULL, padding = NULL, sort = NULL,
  name = property, label = NULL, override = NULL)
scale_nominal(vis, property, domain = NULL, range = NULL, reverse = NULL,
  round = NULL, points = NULL, padding = NULL, sort = NULL,
  name = property, label = NULL, override = NULL)
scale_logical(vis, property, domain = NULL, range = NULL, reverse = NULL,
  round = NULL, points = NULL, padding = NULL, sort = NULL,
  name = property, label = NULL, override = NULL)

Arguments

vis

A ggvis object.

property

The name of a property, such as "x", "y", "fill", "stroke", etc.

domain

The domain of the scale, representing the set of data values. For ordinal scales, a character vector; for quantitative scales, a numeric vector of length two. Either value (but not both) may be NA, in which case domainMin or domainMax

range

The range of the scale, representing the set of visual values.
For numeric values, the range can take the form of a two-element array with
minimum and maximum values. For ordinal data, the range may by an array of
desired output values, which are mapped t

reverse

If true, flips the scale range.

round

If true, rounds numeric output values to integers. This can be
helpful for snapping to the pixel grid.

points

If TRUE (default), distributes the ordinal values over a
quantitative range at uniformly spaced points. The spacing of the points
can be adjusted using the padding property. If FALSE, the ordinal
scale will construct evenly-space

padding

Applies spacing among ordinal elements in the scale range.
The actual effect depends on how the scale is configured. If the points
parameter is true, the padding value is interpreted as a multiple of the
spacing between points. A reasonable value is 1.0,

sort

If TRUE, the values in the scale domain will be sorted
according to their natural order. Default is FALSE.

name

Name of the scale, such as "x", "y", "fill", etc. Can also be an
arbitrary name like "foo".

label

Label for the scale. Used for axis or legend titles.

override

Should the domain specified by this ggvis_scale object
override other ggvis_scale objects for the same scale? Useful when domain is
manually specified. For example, by default, the domain of the scale
will contain the range of the data, but when this is T

`See Also`

scales, scale_numeric,
  https://github.com/trifacta/vega/wiki/Scales#ordinal-scale-properties,
  https://github.com/mbostock/d3/wiki/Ordinal-Scales
Other scales: scale_datetime;
  scale_numeric

`Examples`

Run this codep <- PlantGrowth %>% ggvis(~group, ~weight) %>% layer_points()

p
p %>% scale_nominal("x", padding = 0)
p %>% scale_nominal("x", padding = 1)

p %>% scale_nominal("x", reverse = TRUE)

p <- ToothGrowth %>% group_by(supp) %>%
  ggvis(~len, fill = ~supp) %>%
  layer_histograms(width = 4, stack = TRUE)

# Control range of fill scale
p %>% scale_nominal("fill", range = c("pink", "lightblue"))

# There's no default range when the data is categorical but the output range
# is continuous, as in the case of opacity. In these cases, you can
# manually specify the range for the scale.
mtcars %>% ggvis(x = ~wt, y = ~mpg, opacity = ~factor(cyl)) %>%
  layer_points() %>%
  scale_nominal("opacity", range = c(0.2, 1))
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