Skip to contents

Level-defining helper functions

Source: R/xp_xtras.R
levelers.Rd

as_leveler() is the generic constructor behind every leveler: it tags a character vector x so that set_var_levels() recognizes it as a set of levels rather than a plain formula list. x[1] is mapped to the raw data value .start_index, x[2] to .start_index + 1, and so on. lvl_bin(), lvl_sex(), and lvl_inord() are thin wrappers around as_leveler() for common cases (binary Yes/No, Male/Female sex, and pre-ordered factors, respectively); call as_leveler() directly when defining your own levels, eg more than two categories, a custom starting index, or an unordered custom label set that the built-in wrappers don't cover.

Usage

as_leveler(x, .start_index = 1, .ordered = FALSE)

is_leveler(x)

lvl_bin(x = c("No", "Yes"), .start_index = 0)

lvl_sex()

lvl_inord(x, .start_index = 1, .ordered = TRUE)

Arguments

x

<character> vector of levels

.start_index

<numeric> starting index for levels

.ordered

<logical> should these levels be treated as an ordered factor (see base::factor) wherever they're consumed (eg val2lvl())?

Value

Special character vector suitable to be used as leveler

Examples


# Roll your own leveler for a case the convenience wrappers don't cover,
# eg an unordered, 3-category custom covariate coded 0/1/2 in the data
arm_levels <- as_leveler(c("Placebo", "Low dose", "High dose"), .start_index = 0)
arm_levels
#> [1] "Placebo"   "Low dose"  "High dose"
#> attr(,"class")
#> [1] "xp_levels" "character"
#> attr(,"start")
#> [1] 0
#> attr(,"ordered")
#> [1] FALSE
is_leveler(arm_levels)
#> [1] TRUE

# The convenience wrappers below are just as_leveler() under the hood, eg
# lvl_bin() is equivalent to as_leveler(c("No", "Yes"), .start_index = 0)
set_var_levels(xpdb_x,
  SEX = lvl_sex(),
  MED1 = lvl_bin(),
  MED2 = lvl_inord(c("n","y"), .start_index = 0)
  )
#> 
#> ── ~ xp_xtras object 
#> Model description: NONMEM PK example for xpose
#> run001.lst overview: 
#>  - Software: nonmem 7.3.0 
#>  - Attached files (memory usage 1.6 Mb): 
#>    + obs tabs: $prob no.1: catab001.csv, cotab001, patab001, sdtab001 
#>    + sim tabs: $prob no.2: simtab001.zip 
#>    + output files: run001.cor, run001.cov, run001.ext, run001.grd, run001.phi, run001.shk 
#>    + special: <none> 
#>  - gg_theme: theme_readable 
#>  - xp_theme: xp_xtra_theme new_x$xp_theme 
#>  - Options: dir = data, quiet = FALSE, manual_import = NULL, cvtype = exact