Function builtin_sub 

fn builtin_sub(
    args: &[RValue],
    named: &[(String, RValue)],
) -> Result<RValue, RError>

Replace the first occurrence of a pattern in character strings.

@param pattern character scalar: regular expression or fixed string @param replacement character scalar: replacement text @param x character vector to search @param fixed logical: if TRUE, pattern is a literal string @param ignore.case logical: if TRUE, matching is case-insensitive @return character vector with first match replaced