您可以使用 trim 删除只有 NA 值的外部行和列:

You can use trim to remove exterior rows and columns that only have NA values:

library(raster)
r <- raster(ncols=18,nrows=18)
r[39:49] <- 1
r[205] <- 6
s <- trim(r) 

要将其他值更改为 NA 或从 NA 更改，您可以使用 reclassify.例如，将 NA 更改为 0:

To change other values to or from NA you can use reclassify. For example, to change NA to 0:

x <- reclassify(r, cbind(NA, 0))