Add more specific error message when user passes incorrect matrix format to from_coo

doc/source/whatsnew/v0.25.0.rst

@@ -590,7 +590,7 @@ Sparse
 - Significant speedup in :class:`SparseArray` initialization that benefits most operations, fixing performance regression introduced in v0.20.0 (:issue:`24985`)
 - Bug in :class:`SparseFrame` constructor where passing ``None`` as the data would cause ``default_fill_value`` to be ignored (:issue:`16807`)
 - Bug in :class:`SparseDataFrame` when adding a column in which the length of values does not match length of index, ``AssertionError`` is raised instead of raising ``ValueError`` (:issue:`25484`)
-
+- Introduce a more specific error message in :meth:`_coo_to_sparse_series` so it returns a TypeError for inputs that are not coo matrices (:issue:`26554`)
 
 Other
 ^^^^^

pandas/core/sparse/scipy_sparse.py

@@ -129,23 +129,29 @@ def _coo_to_sparse_series(A, dense_index: bool = False,
 
     Returns
     -------
-    Series or SparseSeries
+    Series or SparseSeries on success
+    TypeError if A is not a coo_matrix
+
     """
     from pandas import SparseDtype
 
-    s = Series(A.data, MultiIndex.from_arrays((A.row, A.col)))
-    s = s.sort_index()
-    if sparse_series:
-        # TODO(SparseSeries): remove this and the sparse_series keyword.
-        # This is just here to avoid a DeprecationWarning when
-        # _coo_to_sparse_series is called via Series.sparse.from_coo
-        s = s.to_sparse()  # TODO: specify kind?
-    else:
-        s = s.astype(SparseDtype(s.dtype))
-    if dense_index:
-        # is there a better constructor method to use here?
-        i = range(A.shape[0])
-        j = range(A.shape[1])
-        ind = MultiIndex.from_product([i, j])
-        s = s.reindex(ind)
-    return s
+    try:
+        s = Series(A.data, MultiIndex.from_arrays((A.row, A.col)))
+        s = s.sort_index()
+        if sparse_series:
+            # TODO(SparseSeries): remove this and the sparse_series keyword.
+            # This is just here to avoid a DeprecationWarning when
+            # _coo_to_sparse_series is called via Series.sparse.from_coo
+            s = s.to_sparse()  # TODO: specify kind?
+        else:
+            s = s.astype(SparseDtype(s.dtype))
+        if dense_index:
+            # is there a better constructor method to use here?
+            i = range(A.shape[0])
+            j = range(A.shape[1])
+            ind = MultiIndex.from_product([i, j])
+            s = s.reindex(ind)
+        return s
+    except AttributeError:
+        raise TypeError('Expected coo_matrix. Got {} instead.'
+                        .format(type(A).__name__))

pandas/tests/arrays/sparse/test_accessor.py

@@ -119,3 +119,10 @@ def test_series_from_coo(self, dtype, dense_index):
             )
 
         tm.assert_series_equal(result, expected)
+
+    @td.skip_if_no_scipy
+    def test_series_from_coo_incorrect_format(self):
+        import scipy.sparse
+        m = scipy.sparse.csr_matrix(np.array([[0, 1], [0, 0]]))
+        with pytest.raises(TypeError):
+            pd.Series.sparse.from_coo(m)