How to manage dynamically-appearing columns within the columns list?

[JoshADHD]

Currently, I have a table that I pivot_wider to reveal the same statistic, but at different points in time. The number of time-points changes dynamically depending on the statistic. I'd like to be able to manage the list of colDef() calls programatically to handle these "new" columns as they appear. Many of the columns are static, but the time-points in particular can be a single point, or upwards of five/six points.

My attempt at this now is:

round_cols <- grep("rd_", colnames(temp), value = TRUE)

round_colDefs <- round_cols %>% seq_along() %>% map(~ {
    colDef(name = paste("round", .x), ...)
})

names(round_colDefs) <- round_cols

round_colDefs <- unlist(round_colDefs, recursive = FALSE)

Then, in the columns argument of reactable()

columns = list(
    name = colDef(name = "player", ...),
    rank = colDef(),
    round_colDefs,
    country = colDef(name = "home", ...)
)

This is returning an error that I'm not providing a named list of colDef() functions.

Any insight into how I might tackle this?

[glin]

Hi,

Is round_colDefs a named list? (could you provide a runnable example?)

If so, you can programmatically create named lists by combining them with c(). For example:

library(reactable)

# Separate named list of colDefs to add. Could be an empty list as well.
extra_columns <- list(
  cyl = colDef(name = "CYL"),
  disp = colDef(name = "DISP")
)

# Method 1: this won't work due to "`columns` must be a named list of column definitions"
# because extra_columns is added as a nested list
reactable(
  mtcars,
  columns = list(
    mpg = colDef(name = "MPG"),
    extra_columns,
    hp = colDef(name = "HP")
  )
)

# This is equivalent to:
reactable(
  mtcars,
  columns = list(
    mpg = colDef(name = "MPG"),
    list(
      cyl = colDef(name = "CYL"),
      disp = colDef(name = "DISP")
    ),
    hp = colDef(name = "HP")
  )
)

#####

# Method 2: this works because c() combines and flattens the named lists
reactable(
  mtcars,
  columns = c(
    list(mpg = colDef(name = "MPG")),
    extra_columns,
    list(hp = colDef(name = "HP"))
  )
)

# This is equivalent to:
reactable(
  mtcars,
  columns = list(
    mpg = colDef(name = "MPG"),
    cyl = colDef(name = "CYL"),
    disp = colDef(name = "DISP"),
    hp = colDef(name = "HP")
  )
)

[JoshADHD]

Thank you, this is exactly the solution I needed!