longitudinal_array {long2lstmarray}

Generate a matrix with various lags from a dataframe

Description

Generate a matrix with various lags from a dataframe

Usage

longitudinal_array(
  data,
  subj_var,
  vars,
  time_var,
  lags,
  label_length = 1,
  label_var = NULL,
  label_output = FALSE,
  time_var_output = FALSE
)

Arguments

data

A data frame, data frame extension (e.g. a tibble).

subj_var

A character string referring to the variable that specifies the "subject" variable.

vars

A character string referring to the variables that contain the variable values.

time_var

A character string referring to the variable that contains the time variable values (e.g. visit day, minutes, years). Important to get the sequences in the right order.

lags

The length of each sliced sequence.

label_length

How many values after are considered to be the label? Default to 1. If label_length = 1, the label value is always the value following the sliced sequence.

label_var

A character string referring to the variables that contain the label variable values.

label_output

logical. if TRUE a list including the matrix with the sliced sequences and a vector with the label is returned.

time_var_output

logical. Is time_var to be included in the final output. Default to FALSE.

Value

If label_output is FALSE, a 3D array with the sliced sequences is returned. The array dimensions are subject, time and variable. If label_output is TRUE, a list with the array and vector with the labels is returned.

Examples

longitudinal_array(alsfrs_data, "subjid", c("p1", "p2", "p3"), 
                   "visdy", lags = 3, label_output = FALSE)
longitudinal_array(alsfrs_data, "subjid", c("p1", "p2", "p3"),
                   "visdy", lags = 3, label_output = FALSE)[1,,]
longitudinal_array(alsfrs_data, "subjid", c("p1", "p2", "p3"), 
                  "visdy", lags = 3, label_output = FALSE)[,1,]
longitudinal_array(alsfrs_data, "subjid", c("p1", "p2", "p3"),
                  "visdy", lags = 3, label_output = FALSE)[,,1]