Spearman-Brown coefficient code producing N/A

How to make this Spearman-Brown coefficient code work? It gives me an output NA

spearman_brown(df[,1], df[,2], short_icc, type = "ICC1", lmer = FALSE)

Data

structure(list(var1 = c("5", "2", "5", "2", "3", "1", "6", "1", 
"4", "5", "5", "2", "2", "3", "1", "3", NA, "5", "7", "5", "2", 
"2", "2", NA, "2", "3", "2", "2", "5", "2", "4", "2", "3", "5", 
"5", "5", "5", "2", "4", NA, "6", "7", "7", "3", "2", "3", "3", 
NA), var2 = c("2", "1", "2", "2", "2", "1", "1", "1", "2", "2", 
"3", "1", "2", "2", "1", "2", NA, "3", "2", "1", "2", "2", "1", 
NA, "1", "2", "1", "1", "2", "1", "1", "2", "2", "2", "4", "3", 
"2", "2", "1", NA, "2", "2", "4", "1", "2", "3", "2", NA)), row.names = c(NA, 
-48L), class = c("tbl_df", "tbl", "data.frame"))

I tried to do it as in the example on this page https://search.r-project.org/CRAN/refmans/splithalfr/html/spearman_brown.html

>Solution :

It is a tibble, so we need to extract with [[ (or $) instead of [, as [ wouldn’t drop the dimensions for tibble or data.table i.e. df[,1] or df[,2] will still be a tibble with a single column where as spearman_brown x and y should be vectors

spearman_brown(df[[1]], df[[2]], short_icc, type = "ICC1", lmer = FALSE)