library(splines2)
set.seed(123)
x <- rnorm(100)
## B-spline basis
bsMat <- bSpline(x, df = 8, degree = 3)
## extract internal knots placed based on the quantile of x
(internal_knots <- knots(bsMat))
## extract boundary knots placed based on the range of x
boundary_knots <- knots(bsMat, type = "boundary")
all.equal(boundary_knots, range(x))
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