aqp (version 2.1.0)

[[: Get column of horizon or site data in a SoilProfileCollection

Description

Get the data from a column accessed by name. Column names other than profile ID are not shared between site and horizons. Bonus: [[ gives access to all site and horizon level variables in tab complete for RStudio using the magrittr pipe operator!

Usage

# S4 method for SoilProfileCollection
[[(x, i, j)

Arguments

x

a SoilProfileCollection

i

an expression resolving to a single column name in site or horizon table

j

(not used)

Examples

data(sp2)
depths(sp2) <- id ~ top + bottom
site(sp2) <- ~ surface

# get with [[
sp2[['surface']]

# get using "unknown" expression:
#  "2nd + 3rd horizon column names"
for(i in horizonNames(sp2)[2:3])
 print(sp2[[i]])

data(sp5)

# some column names to work with
rgb.columns <- c("R25","G25","B25")

res <- lapply(rgb.columns, function(x) {

  # [[ allows you to access column names in a loop
  round(sp5[[x]] * 255)

})

# rename scaled results
names(res) <- paste0(rgb.columns,"_scl")

# add horizon ID to results
result <- data.frame(hzID = hzID(sp5), do.call('cbind', res))
head(result)

# join result back into horizons
horizons(sp5) <- result