Why does "1176413S03" get converted to numeric when using readr::type_convert ?

[shahronak47]

Why does these values get converted into numeric when using readr::type_convert ? I would expect them to stay characters.

x <- c("1176413S03", "1176413S06", "1176413S02", "1176413S08", "1176413S05", "1176413S04")
df <- data.frame(x)
str(df)

'data.frame':	6 obs. of  1 variable:
 $ x: chr  "1176413S03" "1176413S06" "1176413S02" "1176413S08" ...

df1 <- readr::type_convert(df)
str(df1)

'data.frame':	6 obs. of  1 variable:
 $ x: num  1.18e+09 1.18e+12 1.18e+08 1.18e+14 1.18e+11 ...

[joranE]

This behavior appears to happen only for the letters D, E, F, L & S (upper or lower case). E makes sense.

res <- purrr::map_chr(
  .x = LETTERS,
  .f = \(x) {
    d <- readr::type_convert(
      df = data.frame(
        x = glue::glue("1176413{letter}03",letter = x)
      )
    )
    class(d$x)
  }
)

setNames(res,LETTERS)

> setNames(res,LETTERS)
          A           B           C           D           E           F 
"character" "character" "character"   "numeric"   "numeric"   "numeric" 
          G           H           I           J           K           L 
"character" "character" "character" "character" "character"   "numeric" 
          M           N           O           P           Q           R 
"character" "character" "character" "character" "character" "character" 
          S           T           U           V           W           X 
  "numeric" "character" "character" "character" "character" "character" 
          Y           Z 
"character" "character" 

[chainsawriot]

readr/src/QiParsers.h

Lines 157 to 181 in 96ddac3

	* Skim off the exponent.
	*/
	p = pExp;
	if (p != *endptr &&
	(*p == 'E' || *p == 'e' || *p == 'S' || *p == 's' || *p == 'F' ||
	*p == 'f' || *p == 'D' || *p == 'd' || *p == 'L' || *p == 'l')) {
	++p;
	if (p != *endptr && *p == '-') {
	expSign = 1;
	++p;
	} else if (p != *endptr && *p == '+')
	++p;
	else if (!isdigit(*p)) {
	--p;
	goto done;
	}
	while (p != *endptr && isdigit(*p))
	exp = exp * 10 + (*p++ - '0');
	}
	if (expSign)
	exp = fracExp - exp;
	else
	exp = fracExp + exp;
	/*

And vroom doesn't use qiparser