RF: refactor labeltable checking

Put labeltable value checking into Cifti2Label class.

Add converter to check float is between 0 and 1.

Author: matthew-brett

nibabel/cifti2/cifti2.py

@@ -28,6 +28,13 @@
 from ..nifti2 import Nifti2Image
 
 
+def _float_01(val):
+    out = float(val)
+    if out < 0 or out > 1:
+        raise ValueError('Float must be between 0 and 1 inclusive')
+    return out
+
+
 class CIFTI2HeaderError(Exception):
     """ Error in CIFTI2 header
     """
@@ -171,26 +178,14 @@ def __setitem__(self, key, value):
             if key != value.key:
                 raise ValueError("The key and the label's key must agree")
             self._labels[key] = value
-        else:
-            try:
-                key = int(key)
-                v = (str(value[0]),) + tuple(float(v) for v in value[1:] if 0 <= float(v) <= 1)
-                if len(v) != 5:
-                    raise ValueError
-            except:
-                raise ValueError(
-                    'Key must be integer and value a string and 4-tuple of floats between 0 and 1'
-                )
-
-            label = Cifti2Label(
-                key=key,
-                label=v[0],
-                red=v[1],
-                green=v[2],
-                blue=v[3],
-                alpha=v[4]
-            )
-            self._labels[key] = label
+            return
+        if len(value) != 5:
+            raise ValueError('Value should be length 5')
+        try:
+            self._labels[key] = Cifti2Label(*([key] + list(value)))
+        except ValueError:
+            raise ValueError('Key should be int, value should be sequence '
+                             'of str and 4 floats between 0 and 1')
 
     def __delitem__(self, key):
         del self._labels[key]
@@ -215,27 +210,26 @@ class Cifti2Label(xml.XmlSerializable):
 
     Attributes
     ----------
-    key : int
+    key : int, optional
         Integer, data value which is assigned this name and color.
-    label : str
+    label : str, optional
         Name of the label.
-    red : None or float
-        Red color component for label.
-    green : None or float
-        Green color component for label.
-    blue : None or float
-        Blue color component for label.
-    alpha : None or float
-        Alpha color component for label.
+    red : float, optional
+        Red color component for label (between 0 and 1).
+    green : float, optional
+        Green color component for label (between 0 and 1).
+    blue : float, optional
+        Blue color component for label (between 0 and 1).
+    alpha : float, optional
+        Alpha color component for label (between 0 and 1).
     """
-    def __init__(self, key=0, label='', red=0, green=0, blue=0,
-                 alpha=0):
-        self.key = key
-        self.label = label
-        self.red = red
-        self.green = green
-        self.blue = blue
-        self.alpha = alpha
+    def __init__(self, key=0, label='', red=0., green=0., blue=0., alpha=0.):
+        self.key = int(key)
+        self.label = str(label)
+        self.red = _float_01(red)
+        self.green = _float_01(green)
+        self.blue = _float_01(blue)
+        self.alpha = _float_01(alpha)
 
     @property
     def rgba(self):
@@ -251,21 +245,20 @@ def _to_xml_element(self):
             raise CIFTI2HeaderError('The key must be an integer')
         for c_ in ('red', 'blue', 'green', 'alpha'):
             try:
-                v = float(getattr(self, c_))
-                if not (0 <= v <= 1):
-                    raise ValueError
+                v = _float_01(getattr(self, c_))
             except ValueError:
                 raise CIFTI2HeaderError(
-                    'Label invalid %s needs to be a float between 0 and 1. and it is %s' %
-                    (c_, v)
+                    'Label invalid %s needs to be a float between 0 and 1. '
+                    'and it is %s' % (c_, v)
                 )
 
         lab = xml.Element('Label')
         lab.attrib['Key'] = str(self.key)
         lab.text = str(self.label)
 
         for name in ('red', 'green', 'blue', 'alpha'):
-            attr = str(getattr(self, name))
+            val = getattr(self, name)
+            attr = '0' if val == 0 else '1' if val == 1 else str(val)
             lab.attrib[name.capitalize()] = attr
         return lab
 

nibabel/cifti2/tests/test_cifti2.py

@@ -6,8 +6,9 @@
 import numpy as np
 
 from nibabel import cifti2 as ci
+from nibabel.cifti2.cifti2 import _float_01
 
-from nose.tools import assert_equal, assert_raises, assert_is_none
+from nose.tools import assert_true, assert_equal, assert_raises, assert_is_none
 
 
 def compare_xml_leaf(str1, str2):
@@ -57,6 +58,18 @@ def test_cifti2_metadata():
                  '<MetaData><MD><Name>b</Name><Value>bval</Value></MD></MetaData>')
 
 
+def test__float_01():
+    assert_equal(_float_01(0), 0)
+    assert_equal(_float_01(1), 1)
+    assert_equal(_float_01('0'), 0)
+    assert_equal(_float_01('0.2'), 0.2)
+    assert_raises(ValueError, _float_01, 1.1)
+    assert_raises(ValueError, _float_01, -0.1)
+    assert_raises(ValueError, _float_01, 2)
+    assert_raises(ValueError, _float_01, -1)
+    assert_raises(ValueError, _float_01, 'foo')
+
+
 def test_cifti2_labeltable():
     lt = ci.Cifti2LabelTable()
     assert_equal(len(lt), 0)
@@ -84,14 +97,16 @@ def test_cifti2_labeltable():
 
     assert_raises(ValueError, lt.__setitem__, 1, label)
     assert_raises(ValueError, lt.__setitem__, 0, test_tuple[:-1])
-
+    assert_raises(ValueError, lt.__setitem__, 0, ('foo', 1.1, 0, 0, 1))
+    assert_raises(ValueError, lt.__setitem__, 0, ('foo', 1.0, -1, 0, 1))
+    assert_raises(ValueError, lt.__setitem__, 0, ('foo', 1.0, 0, -0.1, 1))
 
 def test_cifti2_label():
     lb = ci.Cifti2Label()
     lb.label = 'Test'
     lb.key = 0
     assert_equal(lb.rgba, (0, 0, 0, 0))
-    assert(compare_xml_leaf(
+    assert_true(compare_xml_leaf(
         lb.to_xml().decode('utf-8'),
         "<Label Key='0' Red='0' Green='0' Blue='0' Alpha='0'>Test</Label>"
     ))
@@ -102,7 +117,7 @@ def test_cifti2_label():
     lb.alpha = 0.3
     assert_equal(lb.rgba, (0, 0.1, 0.2, 0.3))
 
-    assert(compare_xml_leaf(
+    assert_true(compare_xml_leaf(
         lb.to_xml().decode('utf-8'),
         "<Label Key='0' Red='0' Green='0.1' Blue='0.2' Alpha='0.3'>Test</Label>"
     ))