Get base value — get_base_value • clinsight

Adds base value to a long-format data frame.

Usage

get_base_value(
  data,
  var = c(item_name = "Weight"),
  event = c(event_name = "Screening"),
  value_column = "item_value",
  id_column = "subject_id"
)

Arguments

data: data frame in long format.
var: A named character vector with the variable name to use. The name of the character vector should match the column in the data frame with the variable names.
event: A names character vector with the event that identifies the baseline value. The name of the character vector should match the column in the data frame with the event names.
value_column: A string containing the column name with the item values.
id_column: The columns identifying a unique participant (subject_id).

Value

as data frame with an additional column named "base_varname".

Examples

 library(dplyr)
 library(tidyr)
 # create a long time series data frame:
 df <- as.data.frame(EuStockMarkets) |> 
  mutate(time = time(EuStockMarkets)) |>
  pivot_longer(-time)
 output <- get_base_value(df, c("name" = "DAX"), event = c("time" = df$time[1]),
                          value_column = "value", id_column = NULL)