grepal: Get a vector of colors whose names match a regular expression

In unikn: Graphical Elements of the University of Konstanz's Corporate Design

Get a vector of colors whose names match a regular expression

Description

grepal returns a vector of colors whose names match a regular expression (regex).

Usage

grepal(pattern, x = colors(), ignore_case = TRUE, plot = TRUE)

Arguments

pattern	A regular expression (specified as a string/character object).
x	A vector of R color names or a data frame of named colors (i.e., whose names can be searched). Default: x = colors().
ignore_case	Should the case of pattern be ignored (passed to ignore.case of the grep function)? Default: ignore_case = TRUE.
plot	Boolean: Plot the output (using seecol)? Default: plot = TRUE.

Details

By default, the base R vector of named colors (i.e., colors()) is searched for names matching a pattern (which can be a simple string or regular expression).

If x (i.e., the object to be searched) is provided, it is must be a vector of color names or a data frame of named color objects (i.e., a color palette).

If plot = TRUE, grepal also visualizes the detected colors (by passing its result to seecol, as a side-effect).

This function facilitates searching colors by name and yields (a vector of) colors of similar color hue (provided that the color's hue is expressed in a color's name). Its name grepal is an abbreviation of grep and "pal".

See Also

seecol for viewing and comparing color palettes; usecol for using color palettes; simcol for finding similar colors; newpal for defining new color palettes; shades_of to defining shades of a given color; ac for adjusting color transparency; pal_unikn for the default uni.kn color palette.

Other color functions: ac(), demopal(), newpal(), seecol(), shades_of(), simcol(), usecol()

Examples

grepal("tan")

# With regular expressions:
some_grey  <- grepal("gr(a|e)y", plot = FALSE)
start_grey <- grepal("^gr(a|e)y", plot = FALSE)
only_grey  <- grepal("^gr(a|e)y$", plot = FALSE)

length(some_grey)
length(only_grey)

# With other color objects (df as x):
grepal("blau", x = pal_unikn)
grepal("SEE", x = pal_unikn_pref, ignore_case = FALSE)

# Applications:
seecol(grepal("white"), col_bg = "lightblue2", main = "See 'white' colors()")

olives  <- grepal("olive", plot = FALSE)
oranges <- grepal("orange", plot = FALSE)
seecol(list(olives, oranges), 
       pal_names = c("olives", "oranges"), 
       main = "Comparing olives and oranges")

unikn documentation built on May 29, 2024, 10:41 a.m.