An `as.numeric()` in R that warns about non-numeric values

as.numeric.verbose

as.numeric.verbose = function(x) {
    # this code will parse german-style comma-as-decimal numbers or
    # english-style dot-as-decimal numbers.
    x = ifelse(grepl('^\\d+,\\d+$', x, perl=T), sub(',', '.', x, fixed=T), x)
    x.num = as.numeric(x)
    # Find which values got coerced to NA
    coerced = which(!is.na(x) & is.na(x.num))
    if (length(coerced) > 0) {
        cat("Following values coerced to NA:\n")
        print(paste(coerced, x[coerced]))
    }
    x.num
}