Assert input is a character string — assert_string • assertions

Assert input is a character string

Usage

assert_string(x, msg = NULL, call = rlang::caller_env(), arg_name = NULL)

Arguments

x: An object
msg: A character string containing the error message to display if x is not a string
call: Only relevant when pooling assertions into multi-assertion helper functions. See cli_abort for details.
arg_name: Advanced use only. Name of the argument passed (default: NULL, will automatically extract arg_name).

Value

invisible(TRUE) if x is a string, otherwise aborts with the error message specified by msg

Examples

try({
assert_string("a") # Passes
assert_string(c("a", "b", "c")) # Throws default error
assert_string(1:3) # Throws default error
assert_string(c("a", 1, "b"), "Custom error message") # Throws custom error
})
#> Error in eval(expr, envir) : 
#>   'c("a", "b", "c")' is not a string! (length is 3, not 1)