subnome: Substitua Nomes em Uma String

#' mtcars2: Motor Trend Car Road Tests
#'
#' Cópia do mtcars para demonstracao.
#'
#' @format A data frame with 32 observations on 11 (numeric) variables.
#' \describe{
#'   \item{mpg}{Miles/(US) gallon}
#'   \item{cyl}{Number of cylinders}
#'   \item{disp}{Displacement (cu.in.)}
#'   \item{hp}{Gross horsepower}
#'   \item{drat}{Rear axle ratio}
#'   \item{wt}{Weight (1000 lbs)}
#'   \item{qsec}{1/4 mile time}
#'   \item{vs}{Engine (0 = V-shaped, 1 = straight)}
#'   \item{am}{	Transmission (0 = automatic, 1 = manual)}
#'   \item{gear}{Number of forward gears}
#'   \item{carb}{Number of carburetors}
#' }
#' @source mtcars function in datasets package.
"mtcars2"