deal with a.chunks is None; resolves #64

Author: alimanfoo

zarr/creation.py

@@ -244,6 +244,26 @@ def full(shape, fill_value, **kwargs):
     return create(shape=shape, fill_value=fill_value, **kwargs)
 
 
+def _get_shape_chunks(a):
+    shape = None
+    chunks = None
+
+    if hasattr(a, 'shape') and \
+            isinstance(a.shape, tuple):
+        shape = a.shape
+
+        if hasattr(a, 'chunks') and \
+                isinstance(a.chunks, tuple) and \
+                (len(a.chunks) == len(a.shape)):
+            chunks = a.chunks
+
+        elif hasattr(a, 'chunklen'):
+            # bcolz carray
+            chunks = (a.chunklen,) + a.shape[1:]
+
+    return shape, chunks
+
+
 def array(data, **kwargs):
     """Create an array filled with `data`.
 
@@ -279,13 +299,7 @@ def array(data, **kwargs):
     # setup chunks
     chunks = kwargs.pop('chunks', None)
     if chunks is None:
-        # try to use same chunks as data
-        if hasattr(data, 'chunklen'):
-            # bcolz carray
-            chunks = (data.chunklen,) + shape[1:]
-        elif hasattr(data, 'chunks') and len(data.chunks) == len(data.shape):
-            # h5py dataset or zarr array
-            chunks = data.chunks
+        _, chunks = _get_shape_chunks(data)
 
     # instantiate array
     z = create(shape=shape, chunks=chunks, dtype=dtype, **kwargs)
@@ -428,11 +442,11 @@ def open_array(store=None, mode='a', shape=None, chunks=None, dtype=None,
 
 def _like_args(a, kwargs):
 
-    if hasattr(a, 'shape'):
-        kwargs.setdefault('shape', a.shape)
-
-    if hasattr(a, 'chunks'):
-        kwargs.setdefault('chunks', a.chunks)
+    shape, chunks = _get_shape_chunks(a)
+    if shape is not None:
+        kwargs.setdefault('shape', shape)
+    if chunks is not None:
+        kwargs.setdefault('chunks', chunks)
 
     if hasattr(a, 'dtype'):
         kwargs.setdefault('dtype', a.dtype)

zarr/tests/test_creation.py

@@ -21,6 +21,34 @@
 from zarr.codecs import Zlib
 
 
+# something bcolz-like
+class MockBcolzArray(object):
+
+    def __init__(self, data, chunklen):
+        self.data = data
+        self.chunklen = chunklen
+
+    def __getattr__(self, item):
+        return getattr(self.data, item)
+
+    def __getitem__(self, item):
+        return self.data[item]
+
+
+# something h5py-like
+class MockH5pyDataset(object):
+
+    def __init__(self, data, chunks):
+        self.data = data
+        self.chunks = chunks
+
+    def __getattr__(self, item):
+        return getattr(self.data, item)
+
+    def __getitem__(self, item):
+        return self.data[item]
+
+
 def test_array():
 
     # with numpy array
@@ -44,25 +72,23 @@ def test_array():
     eq(z.dtype, z2.dtype)
     assert_array_equal(z[:], z2[:])
 
-    # with something bcolz-like
-    class MockBcolzArray(object):
-
-        def __init__(self, data, chunklen):
-            self.data = data
-            self.chunklen = chunklen
-
-        def __getattr__(self, item):
-            return getattr(self.data, item)
-
-        def __getitem__(self, item):
-            return self.data[item]
-
     b = np.arange(1000).reshape(100, 10)
     c = MockBcolzArray(b, 10)
     z3 = array(c)
     eq(c.shape, z3.shape)
     eq((10, 10), z3.chunks)
 
+    b = np.arange(1000).reshape(100, 10)
+    c = MockH5pyDataset(b, chunks=(10, 2))
+    z4 = array(c)
+    eq(c.shape, z4.shape)
+    eq((10, 2), z4.chunks)
+
+    c = MockH5pyDataset(b, chunks=None)
+    z5 = array(c)
+    eq(c.shape, z5.shape)
+    assert_is_instance(z5.chunks, tuple)
+
 
 def test_empty():
     z = empty(100, chunks=10)
@@ -174,6 +200,7 @@ def test_open_array():
 
 
 def test_empty_like():
+
     # zarr array
     z = empty(100, chunks=10, dtype='f4', compressor=Zlib(5),
               order='F')
@@ -184,18 +211,35 @@ def test_empty_like():
     eq(z.compressor.get_config(), z2.compressor.get_config())
     eq(z.fill_value, z2.fill_value)
     eq(z.order, z2.order)
+
     # numpy array
     a = np.empty(100, dtype='f4')
     z3 = empty_like(a)
     eq(a.shape, z3.shape)
     eq((100,), z3.chunks)
     eq(a.dtype, z3.dtype)
     assert_is_none(z3.fill_value)
+
     # something slightly silly
     a = [0] * 100
     z3 = empty_like(a, shape=200)
     eq((200,), z3.shape)
 
+    # other array-likes
+    b = np.arange(1000).reshape(100, 10)
+    c = MockBcolzArray(b, 10)
+    z = empty_like(c)
+    eq(b.shape, z.shape)
+    eq((10, 10), z.chunks)
+    c = MockH5pyDataset(b, chunks=(10, 2))
+    z = empty_like(c)
+    eq(b.shape, z.shape)
+    eq((10, 2), z.chunks)
+    c = MockH5pyDataset(b, chunks=None)
+    z = empty_like(c)
+    eq(b.shape, z.shape)
+    assert_is_instance(z.chunks, tuple)
+
 
 def test_zeros_like():
     # zarr array