diff --git a/bob/bio/base/algorithm/LDA.py b/bob/bio/base/algorithm/LDA.py
index 37b047bbe1b9ead95c7341618d4bc5fb3cac1edf..83bcc4c770a6dd1d8110e9fce39c99740719496f 100644
--- a/bob/bio/base/algorithm/LDA.py
+++ b/bob/bio/base/algorithm/LDA.py
@@ -56,7 +56,7 @@ class LDA (Algorithm):
 
   def _check_feature(self, feature, projected=False):
     """Checks that the features are appropriate"""
-    if not isinstance(feature, numpy.ndarray) or len(feature.shape) != 1 or feature.dtype != numpy.float64:
+    if not isinstance(feature, numpy.ndarray) or feature.ndim != 1 or feature.dtype != numpy.float64:
       raise ValueError("The given feature is not appropriate")
     index = 1 if projected else 0
     if self.machine is not None and feature.shape[0] != self.machine.shape[index]:
diff --git a/bob/bio/base/algorithm/PCA.py b/bob/bio/base/algorithm/PCA.py
index edac88833cf5911ab61c4eed4289cd48193f46b3..708216e930dcd46c98b7d73497ce43ea6ab64db4 100644
--- a/bob/bio/base/algorithm/PCA.py
+++ b/bob/bio/base/algorithm/PCA.py
@@ -48,7 +48,7 @@ class PCA (Algorithm):
 
   def _check_feature(self, feature, projected=False):
     """Checks that the features are appropriate"""
-    if not isinstance(feature, numpy.ndarray) or len(feature.shape) != 1 or feature.dtype != numpy.float64:
+    if not isinstance(feature, numpy.ndarray) or feature.ndim != 1 or feature.dtype != numpy.float64:
       raise ValueError("The given feature is not appropriate")
     index = 1 if projected else 0
     if self.machine is not None and feature.shape[0] != self.machine.shape[index]: