From 473b78286368efaa78cd20caeb9612f258e8f29d Mon Sep 17 00:00:00 2001
From: rhijmans <r.hijmans@gmail.com>
Date: Sat, 11 Nov 2023 05:18:24 +0100
Subject: [PATCH] fixes #1335

---
 R/extract.R      | 24 +++++++++++++++++-------
 src/extract.cpp  | 45 +++++++++++++++++++++++++++------------------
 src/spatRaster.h |  2 +-
 3 files changed, 45 insertions(+), 26 deletions(-)

diff --git a/R/extract.R b/R/extract.R
index fb6ec68b6..44fa54058 100644
--- a/R/extract.R
+++ b/R/extract.R
@@ -224,15 +224,21 @@ extract_table <- function(x, y, ID=FALSE, weights=FALSE, exact=FALSE, touches=FA
 
 extract_fun <- function(x, y, fun, ID=TRUE, weights=FALSE, exact=FALSE, touches=FALSE, layer=NULL, bind=FALSE, na.rm=FALSE) {
 
-	opt <- spatOptions()
+	nl <- nlyr(x)
+	nf <- length(fun)
+	if ((nf > 1) & (!is.null(layer))) {
+		error("extract", "you cannot use argument 'layer' when using multiple functions")
+	}
 
+	opt <- spatOptions()
 	e <- x@cpp$extractVectorFlat(y@cpp, fun, na.rm, touches[1], "", FALSE, FALSE, weights, exact, opt)
 	x <- messages(x, "extract")
-
-	nl <- nlyr(x)
-	e <- data.frame(matrix(e, ncol=nl, byrow=TRUE))
-	colnames(e) <- names(x)
-
+	e <- data.frame(matrix(e, ncol=nl*nf, byrow=TRUE))
+	if (nf == 1) {
+		colnames(e) <- names(x)
+	} else {
+		colnames(e) <- apply(cbind(rep(fun, each=nl), names(x)), 1, function(i) paste(i, collapse="_"))
+	}
 	if (!is.null(layer)) {
 		e <- cbind(ID=1:nrow(e), e)
 		e <- use_layer(e, y, layer, nlyr(x))
@@ -245,6 +251,7 @@ extract_fun <- function(x, y, fun, ID=TRUE, weights=FALSE, exact=FALSE, touches=
 		if (nrow(e) == nrow(y)) {
 			e <- cbind(y, e)
 		} else {
+			#? can this occur?
 			warn("extract", "cannot return a SpatVector because the number of records extracted does not match he number of rows in y (perhaps you need to use a summarizing function")
 		}
 	} else if (ID) {
@@ -288,7 +295,10 @@ function(x, y, fun=NULL, method="simple", cells=FALSE, xy=FALSE, ID=TRUE, weight
 	} else if (!is.null(fun)) { # nothing to summarize for points
 		txtfun <- .makeTextFun(fun)
 		if (inherits(txtfun, "character")) {
-			if (txtfun == "table") {
+			if (any(txtfun == "table")) {
+				if (length(fun) > 1) {
+					warn("extract", "'table' cannot be combined with other functions")
+				}			
 				if (!is.null(layer)) {
 					warn("extract", "argument 'layer' is ignored when 'fun=table'")
 				}
diff --git a/src/extract.cpp b/src/extract.cpp
index b08b1f2da..54ba24cd6 100644
--- a/src/extract.cpp
+++ b/src/extract.cpp
@@ -898,7 +898,7 @@ std::vector<double> SpatRaster::extractVectorFlat(SpatVector v, std::string fun,
 */
 
 
-std::vector<double> SpatRaster::extractVectorFlat(SpatVector v, std::string fun, bool narm, bool touches, std::string method, bool cells, bool xy, bool weights, bool exact, SpatOptions &opt) {
+std::vector<double> SpatRaster::extractVectorFlat(SpatVector v, std::vector<std::string> funs, bool narm, bool touches, std::string method, bool cells, bool xy, bool weights, bool exact, SpatOptions &opt) {
 
 	if (!source[0].srs.is_same(v.srs, true)) {
 		v = v.project(getSRS("wkt"), false);
@@ -983,19 +983,25 @@ std::vector<double> SpatRaster::extractVectorFlat(SpatVector v, std::string fun,
 
 	SpatRaster r = geometry(1);
 	//std::vector<double> feats(1, 1) ;
-	std::function<double(std::vector<double>&, size_t, size_t)> efun;
-	std::function<double(std::vector<double>&, std::vector<double>&, size_t, size_t)> wfun;
+	std::vector<std::function<double(std::vector<double>&, size_t, size_t)>> efuns;
+	std::vector<std::function<double(std::vector<double>&, std::vector<double>&, size_t, size_t)>> wfuns;
 	bool havefun = false;
-	if (!fun.empty()) {
+	if (!funs.empty()) {
 		if (weights | exact) {
-			if (!getseWfun(wfun, fun, narm)) {
-				setError("not a valid function");
-				return flat;
+			wfuns.resize(funs.size());
+			for (size_t i=0; i<funs.size(); i++) {
+				if (!getseWfun(wfuns[i], funs[i], narm)) {
+					setError(funs[i] + " is not a valid function");
+					return flat;
+				}
 			}
 		} else {
-			if (!getseFun(efun, fun, narm)) {
-				setError("not a valid function");
-				return flat;
+			efuns.resize(funs.size());
+			for (size_t i=0; i<funs.size(); i++) {
+				if (!getseFun(efuns[i], funs[i], narm)) {
+					setError(funs[i] + " is not a valid function");
+					return flat;
+				}
 			}
 		}
 		havefun = true;
@@ -1027,15 +1033,18 @@ std::vector<double> SpatRaster::extractVectorFlat(SpatVector v, std::string fun,
 		if (havefun) {
 			std::vector<std::vector<double>> cvals = extractCell(cell);
 			if (weights | exact) {
-				for (size_t j=0; j<nl; j++) {
-					flat.push_back( wfun(cvals[j], wgt, 0, cvals[j].size()) );
-				}											
+				for (size_t j=0; j<funs.size(); j++) {
+					for (size_t k=0; k<nl; k++) {
+						flat.push_back( wfuns[j](cvals[k], wgt, 0, cvals[k].size()) );
+					}
+				}
 			} else {
-				for (size_t j=0; j<nl; j++) {
-					flat.push_back( efun(cvals[j], 0, cvals[j].size()) );
-				}						
-			}
-			
+				for (size_t j=0; j<funs.size(); j++) {
+					for (size_t k=0; k<nl; k++) {
+						flat.push_back( efuns[j](cvals[k], 0, cvals[k].size()) );
+					}						
+				}
+			}			
 		} else {
 			out[i] = extractCell(cell);
 			if (cells) {
diff --git a/src/spatRaster.h b/src/spatRaster.h
index 9107e147b..ca40bc87d 100644
--- a/src/spatRaster.h
+++ b/src/spatRaster.h
@@ -647,7 +647,7 @@ class SpatRaster {
 		SpatRaster edges(bool classes, std::string type, unsigned directions, double falseval, SpatOptions &opt);
 		SpatRaster extend(SpatExtent e, std::string snap, double fill, SpatOptions &opt);
 		std::vector<std::vector<std::vector<double>>> extractVector(SpatVector v, bool touches, std::string method, bool cells, bool xy, bool weights, bool exact, SpatOptions &opt);
-		std::vector<double> extractVectorFlat(SpatVector v, std::string fun, bool narm, bool touches, std::string method, bool cells, bool xy, bool weights, bool exact, SpatOptions &opt);
+		std::vector<double> extractVectorFlat(SpatVector v, std::vector<std::string> funs, bool narm, bool touches, std::string method, bool cells, bool xy, bool weights, bool exact, SpatOptions &opt);
 		
 		
 		std::vector<double> vectCells(SpatVector v, bool touches, std::string method, bool weights, bool exact, SpatOptions &opt);