Require namespace — require

require_namespace() is ultimately a check which will produce an error on the first package that is not available or meets version requirements. Although this returns TRUE, it is not intended to be used in a conditional statement. Future version may return invisible(). For conditional checks use available_namespace(), which will return a named logical instead.

is_namespace_available() is an alias for available_namespace().

Usage

require_namespace(package, ...)

available_namespace(package, ...)

is_namespace_available(package, ...)

Arguments

package, ...: Package names

Value

require_namespace() TRUE (invisibly) if found; otherwise errors

available_namespace() A named logical vector of same length as input. Vector names are packages and values are TRUE if the package is available and meets the version requirement, otherwise FALSE.

Details

Checks if a package is available and optionally meets a specific version requirement.

Examples

isTRUE(require_namespace("base")) # returns invisibly
#> [1] TRUE
try(require_namespace("1package")) # (using a purposefully bad name)
#> Error : <namespace_error> No package found called '1package'
require_namespace("base", "utils")
try(require_namespace("base >= 3.5", "utils > 4.0", "fuj == 0.0"))
#> Error : <fuj::namespace_version_error> Package version require not met: fuj is 0.2.2.9015 but ==0.0 is required.

# no error check
fuj0 <- if (!available_namespace("fuj == 0.0")) {
  "fuj 0.0 does not exist"
}
fuj0
#> [1] "fuj 0.0 does not exist"