turn line of code into a function, dplyr, R

I need assistance to convert the following working line of code into a function that takes a dataframe, a column name (e.g., year), and a row number (e.g., 4) then returns the same integer result as the one line of code. My attempt below is not working.

library(tidyverse)
library(admiral)
library(lubridate)

date_df <- tribble(
  ~id, ~year,
  1, "2020-01-01",
  2, "2021-06-15",
  3, "2023-12-31",
  4, "1999",
  5, "1978",
  6, "2001-10-07",
)

# This function works, gives result as: 36525
as.integer(as_date(admiral::impute_dtc_dt(dtc = date_df$year[4], highest_imputation = "M", date_imputation = "06-15")) - as_date("1899-12-30")) # Result: 36525


# This doesn't work: My attempt at turning above into a function that takes a dataframe, a column name (e.g., year), and a row number (e.g., 4( then returns the same integer result
impute_year <- function(date_df, year, rownum) {
  as.integer(as_date(admiral::impute_dtc_dt(dtc = date_df$!!year[!!rownum], highest_imputation = "M", date_imputation = "06-15")) - as_date("1899-12-30"))
}

>Solution :

library(tidyverse)
library(admiral)
library(lubridate)

impute_year <- function(date_df, year_col, row_num) {
  as.integer(as_date(admiral::impute_dtc_dt(dtc = date_df[[year_col]][row_num], highest_imputation = "M", date_imputation = "06-15")) - as_date("1899-12-30"))
}

date_df <- tribble(
  ~id, ~year,
  1, "2020-01-01",
  2, "2021-06-15", 
  3, "2023-12-31",
  4, "1999",
  5, "1978",
  6, "2001-10-07"
)

# Test the function
impute_year(date_df, "year", 4) # Returns 36525

In the original code, the line date_df$year[4] directly accessed the 4th element of the year column in the date_df dataframe.
In the function, we need to use the [[ operator to access the column by name (date_df[[year_col]][row_num]). The !! operators used in the original attempt are not necessary here.
The rest of the function logic remains the same, using admiral::impute_dtc_dt() to impute the date and then calculating the number of days since "1899-12-30".
The function now takes three arguments:
date_df: the input dataframe
year_col: the name of the column containing the year data
row_num: the row number to extract the year data from
And it returns the same integer result as the original one-line code.