Merge pull request #352 from thirdwing/master

Enable e.g. 'a[b > 3] = b[b > 3]'

Author: eddelbuettel

inst/include/Rcpp/vector/Subsetter.h

@@ -97,6 +97,30 @@ class SubsetProxy {
         return *this;
     }
 
+    template <int RTYPE_OTHER, template <class> class StoragePolicyOther,int RHS_RTYPE_OTHER, bool RHS_NA_OTHER, typename RHS_T_OTHER>
+    SubsetProxy& operator=(const SubsetProxy<RTYPE_OTHER, StoragePolicyOther, RHS_RTYPE_OTHER, RHS_NA_OTHER, RHS_T_OTHER>& other) {
+
+        Vector<RTYPE_OTHER, StoragePolicyOther> other_vec = other;
+        *this = other_vec;
+        return *this;
+    }
+
+    SubsetProxy& operator=(const SubsetProxy& other) {
+        if (other.indices_n == 1) {
+            for (int i=0; i < indices_n; ++i) {
+                lhs[ indices[i] ] = other.lhs[other.indices[0]];
+            }
+        }
+        else if (indices_n == other.indices_n) {
+            for (int i=0; i < indices_n; ++i)
+                lhs[ indices[i] ] = other.lhs[other.indices[i]];
+            }
+        else {
+            stop("index error");
+        }
+        return *this;
+    }
+
     operator Vector<RTYPE, StoragePolicy>() const {
         return get_vec();
     }

inst/unitTests/cpp/Subset.cpp

@@ -56,3 +56,39 @@ NumericVector subset_test_assign(NumericVector x) {
 NumericVector subset_test_constref(NumericVector const& x, IntegerVector const& y) {
     return x[y];
 }
+
+// [[Rcpp::export]]
+NumericVector subset_assign_subset(NumericVector x) {
+    NumericVector y(x.size());
+    y[x > 3] = x[x > 3];
+    return y;
+}
+
+// [[Rcpp::export]]
+NumericVector subset_assign_subset2(NumericVector x) {
+    NumericVector y(x.size());
+    y[x <= 3] = x[x > 3];
+    return y;
+}
+
+// [[Rcpp::export]]
+NumericVector subset_assign_subset3(NumericVector x) {
+    NumericVector y(x.size());
+    y[x <= 3] = x[3];
+    return y;
+}
+
+// [[Rcpp::export]]
+IntegerVector subset_assign_subset4(NumericVector x) {
+    IntegerVector y(x.size());
+    y[x <= 3] = x[x <= 3];
+    return y;
+}
+
+// [[Rcpp::export]]
+NumericVector subset_assign_subset5(NumericVector x) {
+    NumericVector y(x.size());
+    y[x < 3] = x[x >= 4];
+    return y;
+}
+

inst/unitTests/runit.subset.R

@@ -75,6 +75,15 @@ if (.runThisTest) {
         y <- subset_test_int(x, 0L)
         checkIdentical( attr(y, "foo"), "bar" )
 
+        checkIdentical(subset_assign_subset(1:6), c(0,0,0,4,5,6))
+        
+        checkIdentical(subset_assign_subset2(1:6), c(4,5,6,0,0,0))
+
+        checkIdentical(subset_assign_subset3(1:6), c(4,4,4,0,0,0))
+
+        checkIdentical(subset_assign_subset4(seq(2, 4, 0.2)), c(2L,2L,2L,2L,2L,3L,0L,0L,0L,0L,0L))
+        
+        checkException(subset_assign_subset5(1:6), msg = "index error")
     }
 
 }