Add support of 1D expression in xcsv

include/xtensor/io/xcsv.hpp

@@ -10,7 +10,6 @@
 #ifndef XTENSOR_CSV_HPP
 #define XTENSOR_CSV_HPP
 
-#include <exception>
 #include <istream>
 #include <iterator>
 #include <sstream>
@@ -211,30 +210,40 @@ namespace xt
     {
         using size_type = typename E::size_type;
         const E& ex = e.derived_cast();
-        if (ex.dimension() != 2)
+        if (ex.dimension() == 1)
         {
-            XTENSOR_THROW(std::runtime_error, "Only 2-D expressions can be serialized to CSV");
-        }
-        size_type nbrows = ex.shape()[0], nbcols = ex.shape()[1];
-        auto st = ex.stepper_begin(ex.shape());
-        for (size_type r = 0; r != nbrows; ++r)
-        {
-            for (size_type c = 0; c != nbcols; ++c)
+            const size_type n = ex.shape()[0];
+            for (size_type i = 0; i != n; ++i)
             {
-                stream << *st;
-                if (c != nbcols - 1)
+                stream << ex(i);
+                if (i != n - 1)
                 {
-                    st.step(1);
                     stream << ',';
                 }
-                else
+            }
+            stream << std::endl;
+        }
+        else if (ex.dimension() == 2)
+        {
+            const size_type nbrows = ex.shape()[0];
+            const size_type nbcols = ex.shape()[1];
+            for (size_type r = 0; r != nbrows; ++r)
+            {
+                for (size_type c = 0; c != nbcols; ++c)
                 {
-                    st.reset(1);
-                    st.step(0);
-                    stream << std::endl;
+                    stream << ex(r, c);
+                    if (c != nbcols - 1)
+                    {
+                        stream << ',';
+                    }
                 }
+                stream << std::endl;
             }
         }
+        else
+        {
+            XTENSOR_THROW(std::runtime_error, "Only 1-D and 2-D expressions can be serialized to CSV");
+        }
     }
 
     struct xcsv_config

test/test_xcsv.cpp

@@ -7,17 +7,28 @@
  * The full license is in the file LICENSE, distributed with this software. *
  ****************************************************************************/
 
-#include <iostream>
 #include <sstream>
 
-#include "xtensor/core/xmath.hpp"
 #include "xtensor/io/xcsv.hpp"
 #include "xtensor/io/xio.hpp"
 
 #include "test_common_macros.hpp"
 
 namespace xt
 {
+    TEST(xcsv, load_1D)
+    {
+        const std::string source = "1, 2, 3, 4";
+
+        std::stringstream source_stream(source);
+
+        const xtensor<int, 2> res = load_csv<int>(source_stream);
+
+        const xtensor<int, 2> exp{{1, 2, 3, 4}};
+
+        ASSERT_TRUE(all(equal(res, exp)));
+    }
+
     TEST(xcsv, load_double)
     {
         std::string source = "1.0, 2.0, 3.0, 4.0\n"
@@ -49,6 +60,16 @@ namespace xt
         ASSERT_TRUE(all(equal(res, exp)));
     }
 
+    TEST(xcsv, dump_1D)
+    {
+        xtensor<double, 1> data{{1.0, 2.0, 3.0, 4.0}};
+
+        std::stringstream res;
+
+        dump_csv(res, data);
+        ASSERT_EQ("1,2,3,4\n", res.str());
+    }
+
     TEST(xcsv, dump_double)
     {
         xtensor<double, 2> data{{1.0, 2.0, 3.0, 4.0}, {10.0, 12.0, 15.0, 18.0}};