# colorNumeric

##### Color mapping

Conveniently maps data values (numeric or factor/character) to colors according to a given palette, which can be provided in a variety of formats.

##### Usage

`colorNumeric(palette, domain, na.color = "#808080", alpha = FALSE)`colorBin(palette, domain, bins = 7, pretty = TRUE, na.color = "#808080", alpha = FALSE)

colorQuantile(palette, domain, n = 4, probs = seq(0, 1, length.out = n + 1),
na.color = "#808080", alpha = FALSE)

colorFactor(palette, domain, levels = NULL, ordered = FALSE, na.color = "#808080",
alpha = FALSE)

##### Arguments

- palette
- The colors or color function that values will be mapped to
- domain
- The possible values that can be mapped.
For

`colorNumeric`

and`colorBin`

, this can be a simple numeric range (e.g.`c(0, 100)`

);`colorQuantile`

needs representative numeric data; and`colorFactor`

- na.color
- The color to return for
`NA`

values. Note that`na.color=NA`

is valid. - alpha
- Whether alpha channels should be respected or ignored. If
`TRUE`

then colors without explicit alpha information will be treated as fully opaque. - bins
- Either a numeric vector of two or more unique cut points or a single number (greater than or equal to 2) giving the number of intervals into which the domain values are to be cut.
- pretty
- Whether to use the function
`pretty()`

to generate the bins when the argument`bins`

is a single number. When`pretty = TRUE`

, the actual number of bins may not be the number of bins you - n
- Number of equal-size quantiles desired. For more precise control,
use the
`probs`

argument instead. - probs
- See
`quantile`

. If provided, the`n`

argument is ignored. - levels
- An alternate way of specifying levels; if specified, domain is ignored
- ordered
- If
`TRUE`

and`domain`

needs to be coerced to a factor, treat it as already in the correct order

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##### Details

`colorNumeric`

is a simple linear mapping from continuous numeric data
to an interpolated palette.

`colorBin`

also maps continuous numeric data, but performs
binning based on value (see the `cut`

function).

`colorQuantile`

similarly bins numeric data, but via the
`quantile`

function.

`colorFactor`

maps factors to colors. If the palette is
discrete and has a different number of colors than the number of factors,
interpolation is used.

The `palette`

argument can be any of the following:

- A character vector of RGB or named colors. Examples:
`palette()`

,`c("#000000", "#0000FF", "#FFFFFF")`

,`topo.colors(10)`

- The name of an RColorBrewer palette, e.g.
`"BuPu"`

or `"Greens"`

.
- A function that receives a single value between 0 and 1 and returns a color. Examples:
`colorRamp(c("#000000", "#FFFFFF"), interpolate="spline")`

.
##### Value

- A function that takes a single parameter
`x`

; when called with a
vector of numbers (except for `colorFactor`

, which expects
factors/characters), #RRGGBB color strings are returned (unless
`alpha=TRUE`

in which case #RRGGBBAA may also be possible).

##### Examples

```
pal = colorBin("Greens", domain = 0:100)
pal(runif(10, 60, 100))
# Exponential distribution, mapped continuously
previewColors(colorNumeric("Blues", domain = NULL), sort(rexp(16)))
# Exponential distribution, mapped by interval
previewColors(colorBin("Blues", domain = NULL, bins = 4), sort(rexp(16)))
# Exponential distribution, mapped by quantile
previewColors(colorQuantile("Blues", domain = NULL), sort(rexp(16)))
# Categorical data; by default, the values being colored span the gamut...
previewColors(colorFactor("RdYlBu", domain = NULL), LETTERS[1:5])
# ...unless the data is a factor, without droplevels...
previewColors(colorFactor("RdYlBu", domain = NULL), factor(LETTERS[1:5],
levels = LETTERS))
# ...or the domain is stated explicitly.
previewColors(colorFactor("RdYlBu", levels = LETTERS), LETTERS[1:5])
```

* Documentation reproduced from package leaflet, version 1.0.0,
License: GPL-3 | file LICENSE
*
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