Remove adjacent duplicate values

Removes adjacent duplicate values over the time axis, possibly from a probability vector or matrix (e.g. survival curves). Equality is determined with a numeric tolerance.

For matrices, duplicate detection is done column-wise across all rows. Only the earliest time point in each run of (near-)equal values is kept.

Usage

trim_duplicates(x, times = NULL, tol = 1e-10)

Arguments

x

(numeric() | matrix()) Vector (length = time points) or matrix (rows = observations, columns = time points).

times

(numeric() | NULL) Optional time points corresponding to x. If NULL, extracted from names/colnames.

tol

(numeric(1)) Absolute tolerance used to detect equality between adjacent time points.

Value

A named list with:

• x: numeric vector or matrix with duplicate adjacent time points removed.

• times: numeric vector of retained time points.

Examples

# remove adjacent duplicates from a survival probability vector
surv = c(1, 1, 0.8, 0.8, 0.5, 0.5, 0.2)
trim_duplicates(surv, times = 1:7)
#> $x
#> [1] 1.0 0.8 0.5 0.2
#> 
#> $times
#> [1] 1 3 5 7
#>