R: Examples for 'R.utils::Options'

### ** Examples

local <- Options()

# Query a missing option
cex <- getOption(local, "graphics/cex")
cat("graphics/cex =", cex, "\n")  # Returns NULL

graphics/cex =

# Query a missing option with default value
cex <- getOption(local, "graphics/cex", defaultValue=1)
cat("graphics/cex =", cex, "\n")  # Returns NULL

graphics/cex = 1

# Set option and get previous value
oldCex <- setOption(local, "graphics/cex", 2)
cat("previous graphics/cex =", oldCex, "\n")  # Returns NULL

previous graphics/cex =

# Set option again and get previous value
oldCex <- setOption(local, "graphics/cex", 3)
cat("previous graphics/cex =", oldCex, "\n")  # Returns 2

previous graphics/cex = 2

# Query a missing option with default value, which is ignored
cex <- getOption(local, "graphics/cex", defaultValue=1)
cat("graphics/cex =", cex, "\n")  # Returns 3

graphics/cex = 3

# Query multiple options with multiple default values
multi <- getOption(local, c("graphics/cex", "graphics/pch"), c(1,2))
print(multi)

$`graphics/cex`
[1] 3

$`graphics/pch`
[1] 2

# Check existance of multiple options
has <- hasOption(local, c("graphics/cex", "graphics/pch"))
print(has)

graphics/cex graphics/pch 
        TRUE        FALSE

# Get a subtree of options
graphics <- getOption(local, "graphics")
print(graphics)

$cex
[1] 3

# Get the complete tree of options
all <- getOption(local)
print(all)

$graphics
$graphics$cex
[1] 3

Examples for 'R.utils::Options'

The Options class