added assigning/replacement methods for measurements (#1) and fixed bug that transferred units and band names to new xarrays when using arithmetic operator

Author: 16EAGLE

DESCRIPTION

@@ -1,9 +1,9 @@
 Package: odcr
 Title: Accessing the Open Data Cube from R
-Version: 0.0.1-5
+Version: 0.0.1-6
 Depends:
   R (>= 3.5.0)
-Date: 2021-07-12
+Date: 2021-09-10
 Authors@R: person("Jakob", "Schwalb-Willmann", email = "[email protected]",
   role = c("aut", "cre"), comment = c(ORCID = "0000-0003-2665-1509"))
 Description: An R interface to the Open Data Cube.
@@ -20,5 +20,5 @@ Suggests:
     knitr,
     raster
 BugReports: https://github.com/eo2cube/odcr/issues
-RoxygenNote: 7.1.1
+RoxygenNote: 7.1.2
 VignetteBuilder: knitr

NAMESPACE

@@ -1,5 +1,6 @@
 # Generated by roxygen2: do not edit by hand
 
+S3method("$<-",xarray.core.dataset.Dataset)
 S3method("*",xarray.core.dataarray.DataArray)
 S3method("+",xarray.core.dataarray.DataArray)
 S3method("-",xarray.core.dataarray.DataArray)
@@ -8,6 +9,7 @@ S3method("[",xarray.core.dataarray.DataArray)
 S3method("[",xarray.core.dataset.Dataset)
 S3method("[[",xarray.core.dataarray.DataArray)
 S3method("[[",xarray.core.dataset.Dataset)
+S3method("[[<-",xarray.core.dataset.Dataset)
 S3method(dim,xarray.core.dataarray.DataArray)
 S3method(dim,xarray.core.dataset.Dataset)
 S3method(plot,xarray.core.dataarray.DataArray)
@@ -32,6 +34,7 @@ importFrom(reticulate,dict)
 importFrom(reticulate,import)
 importFrom(reticulate,py_config)
 importFrom(reticulate,py_get_item)
+importFrom(reticulate,py_set_item)
 importFrom(reticulate,use_python)
 importFrom(sf,st_crs)
 importFrom(sf,st_set_crs)

R/internal.R

@@ -107,6 +107,20 @@ out <- function(input, type = 1, ll = NULL, msg = FALSE, sign = "", verbose = ge
   return(y)
 }
 
+#' @keywords internal
+#' @noRd
+.rm_name <- function(x){
+  x$name <- NULL
+  x
+}
+
+#' @keywords internal
+#' @noRd
+.rm_attr <- function(x, attr){
+  x$attrs[[attr]] <- NULL
+  x
+}
+
 #' @importFrom reticulate import
 #' @keywords internal
 #' @noRd

R/xarray_methods.R

@@ -1,16 +1,33 @@
-#' select var with this method
-#' @importFrom reticulate py_get_item
+#' convert index into name
 #' @keywords internal
 #' @noRd
-.index_var <- function(x, ...) {
+.index2name <- function(x, ...){
   i <- list(...)[[1]]
-
   if(is.numeric(i)){
     i <- .get_measurements(x)[i]
   }
+  return(i)
+}
+
+#' select var with this method
+#' @importFrom reticulate py_get_item
+#' @keywords internal
+#' @noRd
+.index_var <- function(x, ...) {
+  i <- .index2name(x, ...)
   return(py_get_item(x, i))
 }
 
+#' assign/set var with this method
+#' @importFrom reticulate py_set_item
+#' @keywords internal
+#' @noRd
+.set_var <- function(x, ..., value){
+  i <- .index2name(x, ...)
+  py_set_item(x, i, value)
+  return(x)
+}
+
 #' select dim with this method
 #' @keywords internal
 #' @noRd
@@ -45,7 +62,7 @@
   return(dims)
 }
 
-#' @title Methods to extract from \code{odcr} classes
+#' @title Methods to extract from or assign to \code{odcr} classes
 #'
 #' @description `[` allows to subset an `xarray` object by its dimensions (see [`dim()`])
 #'
@@ -115,7 +132,7 @@
 #' @rdname Extract
 #' @md
 #'
-#' @param ... numeric or character, index or indices by which to extract (additional) elements
+#' @param ... numeric or character, index or indices by which to extract/assign (additional) elements
 #'
 #' @export
 "[[.xarray.core.dataset.Dataset" <- .index_var
@@ -128,7 +145,7 @@
 #' @rdname Extract
 #' @md
 #'
-#' @param x `xarray` object, the dataset to be subsetted
+#' @param x `xarray` object, the dataset to be subsetted from or assigned to
 #' @param query character vector, one or more time/date character vectors in the format of the time dimension of `x` or an abbreviated form of it (e.g. only the date component)
 #' @param exact_match logical, whether to return only exact matches (default) or to search for closest elements to each element in `query` using `[difftime()]`
 #'
@@ -150,6 +167,19 @@ xar_sel_time <- function(x, query, exact_match = T){
   }
 }
 
+#' @description `[[<-` allows to assign a measurement/variable (e.g. spectral band), either named (character) or indexed (numeric), to an existing `xarray` object.
+#' @md
+#'
+#' @param value `xarray` object, the dataset that should be assigned to `x`
+#' @rdname Extract
+#'
+#' @export
+"[[<-.xarray.core.dataset.Dataset" <- .set_var
+
+#' @rdname Extract
+#'
+#' @export
+"$<-.xarray.core.dataset.Dataset" <- .set_var
 
 
 #' Dimensions of \code{odcr} classes
@@ -295,25 +325,29 @@ plot.xarray.core.dataarray.DataArray <- function(x, ...) {
 #' }
 #' @export
 "+.xarray.core.dataarray.DataArray" <- function(xds, yds) {
-  np$add(xds, yds)
+  y <- np$add(xds, yds)
+  .rm_attr(.rm_name(y), "units")
 }
 
 #' @rdname Arithmetic
 #' @export
 "-.xarray.core.dataarray.DataArray" <- function(xds, yds) {
-  np$subtract(xds, yds)
+  y <- np$subtract(xds, yds)
+  .rm_attr(.rm_name(y), "units")
 }
 
 #' @rdname Arithmetic
 #' @export
 "/.xarray.core.dataarray.DataArray" <- function(xds, yds) {
-  np$divide(xds, yds)
+  y <- np$divide(xds, yds)
+  .rm_attr(.rm_name(y), "units")
 }
 
 #' @rdname Arithmetic
 #' @export
 "*.xarray.core.dataarray.DataArray" <- function(xds, yds) {
-  np$multiply(xds, yds)
+  y <- np$multiply(xds, yds)
+  .rm_attr(.rm_name(y), "units")
 }
 
 #' "xarray.core.dataset.Dataset" class