merge_cov_locf: Merge Time-Varying Covariates by LOCF

In nmw: Understanding Nonlinear Mixed Effects Modeling for Population Pharmacokinetics

Merge Time-Varying Covariates by LOCF

Description

Merge time-varying covariate columns into a NM-style data.frame using LOCF (with LOCB for records before the first source). Subjects/records still NA after LOCF/LOCB can be filled with the column-wise median of cov_df.

Usage

merge_cov_locf(
  nm,
  cov_df,
  value_cols,
  time_col,
  median_fb = TRUE,
  verbose = FALSE,
  subj_col = "SUBJID",
  dat_col = "DAT2",
  tim_col = "TIME"
)

Arguments

nm	data.frame with key columns subj_col, dat_col, tim_col.
cov_df	data.frame with subj_col, time_col, and one or more value columns.
value_cols	character vector of value columns in cov_df to bring into nm.
time_col	name of the time column in cov_df, parsed by parse_dtc.
median_fb	logical. If TRUE (default), fill remaining NA values with the column-wise median of cov_df.
verbose	logical. Print median fill counts. Default FALSE.
subj_col	subject ID column name. Default "SUBJID".
dat_col	date column name in nm. Default "DAT2".
tim_col	time column name in nm. Default "TIME".

Value

nm with value_cols added.

nmw documentation built on May 8, 2026, 9:07 a.m.