FIX for early numpy where astype(..., copy=...) unavailable

jnothman · jnothman · commit c530f5aed460 · 2014-03-12T14:24:26.000+11:00
diff --git a/sklearn/preprocessing/imputation.py b/sklearn/preprocessing/imputation.py
@@ -14,6 +14,7 @@
 from ..utils import atleast2d_or_csr
 from ..utils import atleast2d_or_csc
 from ..utils import as_float_array
+from ..utils.fixes import astype
 
 from ..externals import six
 
@@ -248,7 +249,7 @@ def _sparse_fit(self, X, strategy, missing_values, axis):
                                     X.indptr[1:-1])
 
             # astype necessary for bug in numpy.hsplit before v1.9
-            columns = [col[mask.astype(bool, copy=False)]
+            columns = [col[astype(mask, bool, copy=False)]
                        for col, mask in zip(columns_all, mask_valids)]
 
             # Median
diff --git a/sklearn/utils/fixes.py b/sklearn/utils/fixes.py
@@ -84,3 +84,15 @@ def divide(x1, x2, out=None, dtype=None):
         if out_orig is None and np.isscalar(x1):
             out = np.asscalar(out)
         return out
+
+
+try:
+    np.array(5).astype(float, copy=False)
+except TypeError:
+    # Compat where astype accepted no copy argument
+    def astype(array, dtype, copy=True):
+        if array.dtype == dtype:
+            return array
+        return array.astype(dtype)
+else:
+    astype = np.ndarray.astype
