allow to skip confirmation for load_builtin (NicolasHug#222)

* allow no prompt on Dataset.from_builtin

* update docstring for Dataset.load_builtin

* add Zachary Glassman to contributors

README.md

@@ -87,13 +87,13 @@ cross_validate(algo, data, measures=['RMSE', 'MAE'], cv=5, verbose=True)
 **Output**:
 
 ```
-Evaluating RMSE, MAE of algorithm SVD on 5 split(s).                       
-                                                                           
-            Fold 1  Fold 2  Fold 3  Fold 4  Fold 5  Mean    Std            
-RMSE        0.9311  0.9370  0.9320  0.9317  0.9391  0.9342  0.0032         
-MAE         0.7350  0.7375  0.7341  0.7342  0.7375  0.7357  0.0015         
-Fit time    6.53    7.11    7.23    7.15    3.99    6.40    1.23           
-Test time   0.26    0.26    0.25    0.15    0.13    0.21    0.06 
+Evaluating RMSE, MAE of algorithm SVD on 5 split(s).
+
+            Fold 1  Fold 2  Fold 3  Fold 4  Fold 5  Mean    Std
+RMSE        0.9311  0.9370  0.9320  0.9317  0.9391  0.9342  0.0032
+MAE         0.7350  0.7375  0.7341  0.7342  0.7375  0.7357  0.0015
+Fit time    6.53    7.11    7.23    7.15    3.99    6.40    1.23
+Test time   0.26    0.26    0.25    0.15    0.13    0.21    0.06
 ```
 
 [Surprise](http://surpriselib.com) can do **much** more (e.g,
@@ -190,7 +190,7 @@ The following persons have contributed to [Surprise](http://surpriselib.com):
 caoyi, Олег Демиденко, Charles-Emmanuel Dias, dmamylin, Lauriane Ducasse,
 franckjay, Lukas Galke, Pierre-François Gimenez, Nicolas Hug, Doruk
 Kilitcioglu, Ravi Raju Krishna, Hengji Liu,  Maher Malaeb, Manoj K, Naturale0,
-nju-luke, Skywhat, David Stevens, Mike Lee Williams, Chenchen Xu, YaoZh1918.
+nju-luke, Skywhat, David Stevens, Mike Lee Williams, Chenchen Xu, YaoZh1918, Zachary Glassman.
 
 Thanks a lot :) !
 

surprise/dataset.py

@@ -64,7 +64,7 @@ def __init__(self, reader=None, rating_scale=None):
             self.rating_scale = self.reader.rating_scale
 
     @classmethod
-    def load_builtin(cls, name='ml-100k'):
+    def load_builtin(cls, name='ml-100k', prompt=True):
         """Load a built-in dataset.
 
         If the dataset has not already been loaded, it will be downloaded and
@@ -76,6 +76,9 @@ def load_builtin(cls, name='ml-100k'):
             name(:obj:`string`): The name of the built-in dataset to load.
                 Accepted values are 'ml-100k', 'ml-1m', and 'jester'.
                 Default is 'ml-100k'.
+            prompt(:obj:`bool`): Prompt before downloading if dataset is not
+                already on disk.
+                Default is True.
 
         Returns:
             A :obj:`Dataset` object.
@@ -93,7 +96,7 @@ def load_builtin(cls, name='ml-100k'):
 
         # if dataset does not exist, offer to download it
         if not os.path.isfile(dataset.path):
-            answered = False
+            answered = not prompt
             while not answered:
                 print('Dataset ' + name + ' could not be found. Do you want '
                       'to download it? [Y/n] ', end='')