allow to init with shape, just like a numpy.recarray

dynamicsizerecarray/__init__.py

@@ -8,7 +8,7 @@ class DynamicSizeRecarray:
     A dynamic, appendable implementation of numpy.core.records.recarray.
     """
 
-    def __init__(self, recarray=None, dtype=None):
+    def __init__(self, recarray=None, dtype=None, shape=0):
         """
         Either provide an existing recarray 'recarray' or
         provide the 'dtype' to start with an empty recarray.
@@ -19,6 +19,8 @@ def __init__(self, recarray=None, dtype=None):
             The start of the dynamic recarray.
         dtype : list(tuple("key", "dtype_str")), default=None
             The dtype of the dynamic recarray.
+        shape : int
+            The initial size. (Same as in np.core.records.recarray)
         """
         self._size = 0
         if recarray is None and dtype == None:
@@ -28,19 +30,24 @@ def __init__(self, recarray=None, dtype=None):
                 "Expected either one of 'recarray' or' dtype' to be 'None'"
             )
 
+        _minimal_capacity = 2
+
         if dtype:
-            recarray = np.core.records.recarray(
-                shape=0,
+            if shape < 0:
+                raise AttributeError("Expected shape >= 0.")
+            initial_capacity = np.max([_minimal_capacity, shape])
+            self._recarray = np.core.records.recarray(
+                shape=initial_capacity,
                 dtype=dtype,
             )
-
-        _minimal_capacity = 2
-        initial_capacity = np.max([_minimal_capacity, len(recarray)])
-        self._recarray = np.core.records.recarray(
-            shape=initial_capacity,
-            dtype=recarray.dtype,
-        )
-        self.append_recarray(recarray=recarray)
+            self._size = shape
+        else:
+            initial_capacity = np.max([_minimal_capacity, len(recarray)])
+            self._recarray = np.core.records.recarray(
+                shape=initial_capacity,
+                dtype=recarray.dtype,
+            )
+            self.append_recarray(recarray=recarray)
 
     @property
     def shape(self):

dynamicsizerecarray/tests/test_init_shape.py

@@ -0,0 +1,21 @@
+import dynamicsizerecarray
+import pytest
+import numpy as np
+
+def test_init_with_shape():
+    dra = dynamicsizerecarray.DynamicSizeRecarray(
+        dtype=[("a", "i8"), ("b", "u2")],
+        shape=13,
+    )
+
+    assert len(dra) == 13
+    assert dra._capacity() == 13
+
+
+def test_init_negative_shape():
+    with pytest.raises(AttributeError):
+        dra = dynamicsizerecarray.DynamicSizeRecarray(
+            dtype=[("a", "i8")],
+            shape=-1,
+        )
+

dynamicsizerecarray/version.py

@@ -1 +1 @@
-__version__ = "0.0.9"
+__version__ = "0.0.10"