ENH: Better error message for invalid axis

shoyer · shoyer · commit 4e5471792884 · 2016-08-06T23:10:20.000-07:00
xref GH7915

Currently, writing array.max(axis=[0, 1]) doesn't mention you can use a tuple
for the axis argument -- it just says "an integer is required".
diff --git a/numpy/core/src/multiarray/conversion_utils.c b/numpy/core/src/multiarray/conversion_utils.c
@@ -289,7 +289,7 @@ PyArray_ConvertMultiAxis(PyObject *axis_in, int ndim, npy_bool *out_axis_flags)
         memset(out_axis_flags, 0, ndim);
 
         axis = PyArray_PyIntAsInt_ErrMsg(axis_in,
-                                   "an integer is required for the axis");
+                               "an integer or tuple is required for the axis");
         axis_orig = axis;
 
         if (error_converting(axis)) {
diff --git a/numpy/core/tests/test_ufunc.py b/numpy/core/tests/test_ufunc.py
@@ -7,8 +7,8 @@
 from numpy.core.test_rational import rational, test_add, test_add_rationals
 from numpy.testing import (
     TestCase, run_module_suite, assert_, assert_equal, assert_raises,
-    assert_array_equal, assert_almost_equal, assert_array_almost_equal,
-    assert_no_warnings
+    assert_raises_regex, assert_array_equal, assert_almost_equal,
+    assert_array_almost_equal, assert_no_warnings
 )
 
 
@@ -1197,6 +1197,7 @@ def test_reduce_arguments(self):
         assert_raises(TypeError, f, d, axis="invalid")
         assert_raises(TypeError, f, d, axis="invalid", dtype=None,
                       keepdims=True)
+        assert_raises_regex(TypeError, "integer or tuple", f, d, axis=[0])
         # invalid dtype
         assert_raises(TypeError, f, d, 0, "invalid")
         assert_raises(TypeError, f, d, dtype="invalid")
@@ -1212,7 +1213,7 @@ def test_reduce_arguments(self):
         assert_raises(TypeError, f, d, 0, keepdims="invalid", dtype="invalid",
                      out=None)
 
-        # invalid keyord
+        # invalid keyword
         assert_raises(TypeError, f, d, axis=0, dtype=None, invalid=0)
         assert_raises(TypeError, f, d, invalid=0)
         assert_raises(TypeError, f, d, 0, keepdims=True, invalid="invalid",
