R/split.R
split-SoilProfileCollection-method.RdThis function splits a SoilProfileCollection into a list of SoilProfileCollection objects using a site-level attribute to define groups or profile ID (idname(x)).
# S4 method for SoilProfileCollection
split(x, f, drop = TRUE, ...)SoilProfileCollection object
character vector naming a single site-level attribute that defines groups, a ‘factor’ in the sense that as.factor(f) defines the grouping, or a list of such factors in which case their interaction is used for the grouping.
logical indicating if levels that do not occur should be dropped (if f is a factor or a list). When drop=FALSE and f contains missing values an additional group "missing" is returned.
additional arguments are ignored
A list of SoilProfileCollection or NULL for empty result.
As of aqp 1.25, omission of f argument is no longer possible, as the base R generic is overloaded by this SoilProfileCollection method. This used to result in an "identity" split, according to idname(x), e.g. a list as long as length(x), with a single-profile SoilProfileCollection per list element. Replicate this behavior using f = idname(x) or f = profile_id(x).
data(sp2)
depths(sp2) <- id ~ top + bottom
# add a more interesting site-level attribute
site(sp2) <- ~ surface
# using identity site-level attribute (profile ID)
p1 <- split(sp2, f = idname(sp2))
#> converting id to factor
names(p1)
#> [1] "hon-1" "hon-10" "hon-11" "hon-13" "hon-14" "hon-17" "hon-18" "hon-19"
#> [9] "hon-2" "hon-20" "hon-21" "hon-22" "hon-3" "hon-4" "hon-5" "hon-6"
#> [17] "hon-7" "hon-8"
length(p1)
#> [1] 18
# using vector equal in length to number of profiles (profile ID, again)
p2 <- split(sp2, f = profile_id(sp2))
names(p2)
#> [1] "hon-1" "hon-10" "hon-11" "hon-13" "hon-14" "hon-17" "hon-18" "hon-19"
#> [9] "hon-2" "hon-20" "hon-21" "hon-22" "hon-3" "hon-4" "hon-5" "hon-6"
#> [17] "hon-7" "hon-8"
length(p2)
#> [1] 18
# which are both equivalent to setting `f` to NULL
p3 <- split(sp2, f = NULL)
names(p3)
#> [1] "hon-1" "hon-10" "hon-11" "hon-13" "hon-14" "hon-17" "hon-18" "hon-19"
#> [9] "hon-2" "hon-20" "hon-21" "hon-22" "hon-3" "hon-4" "hon-5" "hon-6"
#> [17] "hon-7" "hon-8"
length(p3)
#> [1] 18
# split on surface (age) site-level var
p4 <- split(sp2, f = "surface")
names(p4)
#> [1] "holocene" "lower modesto" "upper modesto" "lower riverbank"
#> [5] "upper riverbank" "lower laguna"
length(p4) # 5 unique "surfaces", 5 SPCs in result list
#> [1] 6