Merge pull request #516 from pauldmccarthy/wrapstruct_fix

MRG: Bugfix to WrapStruct.get

A minor bug in WrapStruct.get - it fails for header fields with values that evaluates to False (e.g. 0)

Author: matthew-brett

nibabel/tests/test_wrapstruct.py

@@ -183,6 +183,17 @@ def test_mappingness(self):
         assert_equal(hdr.get(keys[0]), vals[0])
         assert_equal(hdr.get(keys[0], 'default'), vals[0])
 
+        # make sure .get returns values which evaluate to False. We have to
+        # use a different falsy value depending on the data type of the first
+        # header field.
+        falsyval = 0 if np.issubdtype(hdr_dt[0], np.number) else b''
+
+        hdr[keys[0]] = falsyval
+        assert_equal(hdr[keys[0]], falsyval)
+        assert_equal(hdr.get(keys[0]), falsyval)
+        assert_equal(hdr.get(keys[0], -1), falsyval)
+
+
     def test_endianness_ro(self):
         # endianness is a read only property
         ''' Its use in initialization tested in the init tests.

nibabel/wrapstruct.py

@@ -343,7 +343,7 @@ def items(self):
 
     def get(self, k, d=None):
         ''' Return value for the key k if present or d otherwise'''
-        return (k in self.keys()) and self._structarr[k] or d
+        return self._structarr[k] if k in self.keys() else d
 
     def check_fix(self, logger=None, error_level=None):
         ''' Check structured data with checks