1 2empty_result <- function(text, pattern, perl=TRUE, ...) { 3 match <- regexpr(pattern, text, perl = perl, ...) 4 num_groups <- length(attr(match, "capture.names")) 5 structure( 6 c( 7 replicate(num_groups, list(), simplify = FALSE), 8 list(character()), 9 list(list()) 10 ), 11 names = c(attr(match, "capture.names"), ".text", ".match"), 12 row.names = integer(0), 13 class = c("tbl_df", "tbl", "data.frame") 14 ) 15} 16