Removing holes from polygons in R sf

Following https://github.com/r-spatial/sf/issues/609#issuecomment-357426716, this could work:

library(sf)
outer = matrix(c(0,0,10,0,10,10,0,10,0,0),ncol=2, byrow=TRUE)
hole1 = matrix(c(1,1,1,2,2,2,2,1,1,1),ncol=2, byrow=TRUE)
hole2 = matrix(c(5,5,5,6,6,6,6,5,5,5),ncol=2, byrow=TRUE)
pts = list(outer, hole1, hole2)
pl1 = st_geometry(st_polygon(pts))

plot(pl1)

pl2 <- st_multipolygon(lapply(pl1, function(x) x[1]))
plot(pl2)

^{Created on 2018-10-05 by the reprex package (v0.2.1)}

Package nngeo introduced a function to do this after this question was answered by @lbusett (and references him in the description, well done).

So you can use:

nngeo::st_remove_holes(your_sf_object)

See https://rdrr.io/cran/nngeo/man/st_remove_holes.html

sfheaders::sf_remove_holes() can also do this

sfheaders::sf_remove_holes(pl1)
POLYGON ((0 0, 10 0, 10 10, 0 10, 0 0))