Add doctests to some of this stuff.

1 files changed, 88 insertions, 1 deletions

diff --git a/dict_utils.py b/dict_utils.py
index 74e8fda..6dd79f3 100644
--- a/dict_utils.py
+++ b/dict_utils.py
@@ -11,6 +11,21 @@ def init_or_inc(
     init_value: Any = 1,
     inc_function: Callable[..., Any] = lambda x: x + 1
 ) -> bool:
+    """
+    Initialize a dict value (if it doesn't exist) or increments it (using the
+    inc_function, which is customizable) if it already does exist.  Returns
+    True if the key already existed or False otherwise.
+
+    >>> d = {}
+    >>> init_or_inc(d, "test")
+    False
+    >>> init_or_inc(d, "test")
+    True
+    >>> init_or_inc(d, 'ing')
+    False
+    >>> d
+    {'test': 2, 'ing': 1}
+    """
     if key in d.keys():
         d[key] = inc_function(d[key])
         return True
@@ -19,6 +34,10 @@ def init_or_inc(
 
 
 def shard(d: Dict[Any, Any], size: int) -> Iterator[Dict[Any, Any]]:
+    """
+    Shards a dict into N subdicts which, together, contain all keys/values
+    from the original unsharded dict.
+    """
     items = d.items()
     for x in range(0, len(d), size):
         yield {key: value for (key, value) in islice(items, x, x + size)}
@@ -42,11 +61,22 @@ def coalesce(
         *,
         aggregation_function: Callable[[Any, Any], Any] = coalesce_by_creating_list
 ) -> Dict[Any, Any]:
+    """Merge N dicts into one dict containing the union of all keys/values in
+    the input dicts.  When keys collide, apply the aggregation_function which,
+    by default, creates a list of values.  See also coalesce_by_creating_set or
+    provide a user defined aggregation_function.
+
+    >>> a = {'a': 1, 'b': 2}
+    >>> b = {'b': 1, 'c': 2, 'd': 3}
+    >>> c = {'c': 1, 'd': 2}
+    >>> coalesce([a, b, c])
+    {'a': 1, 'b': [1, 2], 'c': [1, 2], 'd': [2, 3]}
+    """
     out: Dict[Any, Any] = {}
     for d in inputs:
         for key in d:
             if key in out:
-                value = aggregation_function(d[key], out[key])
+                value = aggregation_function(key, d[key], out[key])
             else:
                 value = d[key]
             out[key] = value
@@ -54,32 +84,89 @@ def coalesce(
 
 
 def item_with_max_value(d: Dict[Any, Any]) -> Tuple[Any, Any]:
+    """Returns the key and value with the max value in a dict.
+
+    >>> d = {'a': 1, 'b': 2, 'c': 3}
+    >>> item_with_max_value(d)
+    ('c', 3)
+    >>> item_with_max_value({})
+    Traceback (most recent call last):
+    ...
+    ValueError: max() arg is an empty sequence
+    """
     return max(d.items(), key=lambda _: _[1])
 
 
 def item_with_min_value(d: Dict[Any, Any]) -> Tuple[Any, Any]:
+    """Returns the key and value with the min value in a dict.
+
+    >>> d = {'a': 1, 'b': 2, 'c': 3}
+    >>> item_with_min_value(d)
+    ('a', 1)
+    """
     return min(d.items(), key=lambda _: _[1])
 
 
 def key_with_max_value(d: Dict[Any, Any]) -> Any:
+    """Returns the key with the max value in the dict.
+
+    >>> d = {'a': 1, 'b': 2, 'c': 3}
+    >>> key_with_max_value(d)
+    'c'
+    """
     return item_with_max_value(d)[0]
 
 
 def key_with_min_value(d: Dict[Any, Any]) -> Any:
+    """Returns the key with the min value in the dict.
+
+    >>> d = {'a': 1, 'b': 2, 'c': 3}
+    >>> key_with_min_value(d)
+    'a'
+    """
     return item_with_min_value(d)[0]
 
 
 def max_value(d: Dict[Any, Any]) -> Any:
+    """Returns the maximum value in the dict.
+
+    >>> d = {'a': 1, 'b': 2, 'c': 3}
+    >>> max_value(d)
+    3
+    """
     return item_with_max_value(d)[1]
 
 
 def min_value(d: Dict[Any, Any]) -> Any:
+    """Returns the minimum value in the dict.
+
+    >>> d = {'a': 1, 'b': 2, 'c': 3}
+    >>> min_value(d)
+    1
+    """
     return item_with_min_value(d)[1]
 
 
 def max_key(d: Dict[Any, Any]) -> Any:
+    """Returns the maximum key in dict (ignoring values totally)
+
+    >>> d = {'a': 3, 'b': 2, 'c': 1}
+    >>> max_key(d)
+    'c'
+    """
     return max(d.keys())
 
 
 def min_key(d: Dict[Any, Any]) -> Any:
+    """Returns the minimum key in dict (ignoring values totally)
+
+    >>> d = {'a': 3, 'b': 2, 'c': 1}
+    >>> min_key(d)
+    'a'
+    """
     return min(d.keys())
+
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()