added getitem and where functionality to Table

python/damask/_table.py

@@ -33,6 +33,10 @@ class Table:
         """Brief overview."""
         return '\n'.join(['# '+c for c in self.comments])+'\n'+self.data.__repr__()
 
+    def __getitem__(self,item):
+        """Return slice according to item."""
+        return self.__class__(data=self.data[item],shapes=self.shapes,comments=self.comments)
+
     def __len__(self):
         """Number of rows."""
         return len(self.data)
@@ -45,6 +49,15 @@ class Table:
         """Copy Table."""
         return self.__copy__()
 
+    def where(self,expression):
+        """
+        Return boolean array corresponding to interpolated expression being True.
+
+        Table columns are addressed as #column# and will have appropriate shapes.
+
+        """
+        return eval(re.sub('#(.+?)#',r'self.get("\1")',expression))
+
 
     def _label_discrete(self):
         """Label data individually, e.g. v v v ==> 1_v 2_v 3_v."""

python/tests/test_Table.py

@@ -8,7 +8,7 @@ from damask import Table
 def default():
     """Simple Table."""
     x = np.ones((5,13),dtype=float)
-    return Table(x,{'F':(3,3),'v':(3,),'s':(1,)},['test data','contains only ones'])
+    return Table(x,{'F':(3,3),'v':(3,),'s':(1,)},['test data','contains five rows of only ones'])
 
 @pytest.fixture
 def reference_dir(reference_dir_base):
@@ -20,8 +20,9 @@ class TestTable:
     def test_repr(self,default):
         print(default)
 
-    def test_len(self):
-        len(Table(np.random.rand(7,3),{'X':3})) == 7
+    @pytest.mark.parametrize('N',[10,40])
+    def test_len(self,N):
+        len(Table(np.random.rand(N,3),{'X':3})) == N
 
     def test_get_scalar(self,default):
         d = default.get('s')
@@ -39,6 +40,16 @@ class TestTable:
         d = default.get('5_F')
         assert np.allclose(d,1.0) and d.shape[1:] == (1,)
 
+    @pytest.mark.parametrize('N',[10,40])
+    def test_getitem(self,N):
+        assert len(Table(np.random.rand(N,1),{'X':1})[:N//2]) == N//2
+
+    @pytest.mark.parametrize('N',[10,40])
+    @pytest.mark.parametrize('limit',[0.1,0.6])
+    def test_where(self,N,limit):
+        r = Table(np.random.rand(N,1),{'X':1})
+        assert np.all(r[r.where(f'#X# > {limit}')].get('X') > limit)
+
     @pytest.mark.parametrize('mode',['str','path'])
     def test_write_read(self,default,tmp_path,mode):
         default.save(tmp_path/'default.txt')