-

cool-RR · cool-RR · commit 59edf10c44d5 · 2013-08-17T02:52:25.000+03:00
diff --git a/python_toolbox/dict_tools.py b/python_toolbox/dict_tools.py
@@ -3,6 +3,8 @@
 
 '''Defines several functions that may be useful when working with dicts.'''
 
+import collections
+
 from python_toolbox import cute_iter_tools
 from python_toolbox import comparison_tools
 
@@ -141,4 +143,43 @@ def sum_dicts(dicts):
     result = {}
     for dict_ in dicts:
         result.update(dict_)
-    return result
+    return result
+
+
+def remove_keys(d, keys_to_remove):
+    '''
+    Remove keys from a dict.
+    
+    `keys_to_remove` is allowed to be either an iterable (in which case it will
+    be iterated on and keys with the same name will be removed), a container
+    (in which case this function will iterate over the keys of the dict, and if
+    they're contained they'll be removed), or a filter function (in which case
+    this function will iterate over the keys of the dict, and if they pass the
+    filter function they'll be removed.)
+    
+    If key doesn't exist, doesn't raise an exception.    
+    '''
+    if isinstance(keys_to_remove, collections.Iterable):
+        for key in keys_to_remove:
+            try:
+                del d[key]
+            except KeyError:
+                pass
+    else:
+        if isinstance(keys_to_remove, collections.Container):
+            filter_function = lambda value: value in keys_to_remove
+        else:
+            assert isinstance(keys_to_remove, collections.Callable)
+            filter_function = keys_to_remove
+        for key in list(d.keys()):
+            if filter_function(key):
+                del d[key]
+            
+            
+        
+    
+    
+    
+    
+    
+    
diff --git a/test_python_toolbox/test_dict_tools/test_remove_keys.py b/test_python_toolbox/test_dict_tools/test_remove_keys.py
@@ -0,0 +1,33 @@
+# Copyright 2009-2013 Ram Rachum.
+# This program is distributed under the MIT license.
+
+import numbers
+
+from python_toolbox.dict_tools import remove_keys
+
+
+def test():
+    '''Test the basic workings of `sum_dicts`.'''
+    origin_dict = {1: 2, 3: 4, 5: 6, 7: 8, 9: 10, 11: 12, 13: 14, 15: 16,}
+    
+    not_divide_by_three_dict = dict(origin_dict)
+    remove_keys(not_divide_by_three_dict, xrange(0, 50, 3))
+    assert not_divide_by_three_dict == {1: 2, 5: 6, 7: 8, 11: 12, 13: 14}
+    
+    below_ten_dict = dict(origin_dict)
+    remove_keys(below_ten_dict, lambda value: value >= 10)
+    assert below_ten_dict == {1: 2, 3: 4, 5: 6, 7: 8, 9: 10}
+    
+    class HoledNumbersContainer(object):
+        '''Contains only numbers that have a digit with a hole in it.'''
+        def __contains__(self, number):
+            if not isinstance(number, numbers.Integral):
+                return False
+            return bool(set(str(number)).intersection({'0', '4', '6', '8', '9'}))
+            
+    
+    non_holed_numbers_dict = dict(origin_dict)
+    remove_keys(non_holed_numbers_dict, HoledNumbersContainer())
+    assert non_holed_numbers_dict == {1: 2, 3: 4, 5: 6, 7: 8, 11: 12, 13: 14,
+                                      15: 16,}
+    
