fixes #654

Author: jph00

fastcore/_modidx.py

@@ -90,6 +90,7 @@
                                  'fastcore.basics._clsmethod': ('basics.html#_clsmethod', 'fastcore/basics.py'),
                                  'fastcore.basics._clsmethod.__get__': ('basics.html#_clsmethod.__get__', 'fastcore/basics.py'),
                                  'fastcore.basics._clsmethod.__init__': ('basics.html#_clsmethod.__init__', 'fastcore/basics.py'),
+                                 'fastcore.basics._conv_key': ('basics.html#_conv_key', 'fastcore/basics.py'),
                                  'fastcore.basics._eval_type': ('basics.html#_eval_type', 'fastcore/basics.py'),
                                  'fastcore.basics._get_op': ('basics.html#_get_op', 'fastcore/basics.py'),
                                  'fastcore.basics._ispy3_10': ('basics.html#_ispy3_10', 'fastcore/basics.py'),

fastcore/basics.py

@@ -618,12 +618,16 @@ def range_of(x):
     return list(range(len(x)))
 
 # %% ../nbs/01_basics.ipynb
+def _conv_key(k):
+    if   isinstance(k,int):   return itemgetter(k)
+    elif isinstance(k,str):   return attrgetter(k)
+    elif isinstance(k,tuple): return lambda x: tuple(_conv_key(o)(x) for o in k)
+    return k
+
 def groupby(x, key, val=noop):
     "Like `itertools.groupby` but doesn't need to be sorted, and isn't lazy, plus some extensions"
-    if   isinstance(key,int): key = itemgetter(key)
-    elif isinstance(key,str): key = attrgetter(key)
-    if   isinstance(val,int): val = itemgetter(val)
-    elif isinstance(val,str): val = attrgetter(val)
+    key = _conv_key(key)
+    val = _conv_key(val)
     res = {}
     for o in x: res.setdefault(key(o), []).append(val(o))
     return res

fastcore/foundation.py

@@ -112,7 +112,7 @@ def __init__(self, items=None, *rest, use_list=False, match=None):
     def _xtra(self): return None
     def _new(self, items, *args, **kwargs): return type(self)(items, *args, use_list=None, **kwargs)
     def __getitem__(self, idx):
-        if isinstance(idx,int): return self.items[idx]
+        if isinstance(idx,int) and not hasattr(self.items,'iloc'): return self.items[idx]
         return self._get(idx) if is_indexer(idx) else L(self._get(idx), use_list=None)
     def copy(self): return self._new(self.items.copy())
 

nbs/01_basics.ipynb

@@ -685,7 +685,7 @@
       "text/markdown": [
        "---\n",
        "\n",
-       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L113){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
+       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L114){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
        "\n",
        "### get_class\n",
        "\n",
@@ -697,7 +697,7 @@
       "text/plain": [
        "---\n",
        "\n",
-       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L113){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
+       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L114){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
        "\n",
        "### get_class\n",
        "\n",
@@ -875,7 +875,7 @@
       "text/markdown": [
        "---\n",
        "\n",
-       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L157){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
+       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L158){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
        "\n",
        "#### ignore_exceptions\n",
        "\n",
@@ -886,7 +886,7 @@
       "text/plain": [
        "---\n",
        "\n",
-       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L157){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
+       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L158){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
        "\n",
        "#### ignore_exceptions\n",
        "\n",
@@ -2910,7 +2910,7 @@
       "text/markdown": [
        "---\n",
        "\n",
-       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L524){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
+       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L525){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
        "\n",
        "#### GetAttr\n",
        "\n",
@@ -2921,7 +2921,7 @@
       "text/plain": [
        "---\n",
        "\n",
-       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L524){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
+       "[source](https://github.com/AnswerDotAI/fastcore/blob/master/fastcore/basics.py#L525){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
        "\n",
        "#### GetAttr\n",
        "\n",
@@ -3601,12 +3601,16 @@
    "outputs": [],
    "source": [
     "#|export\n",
+    "def _conv_key(k):\n",
+    "    if   isinstance(k,int):   return itemgetter(k)\n",
+    "    elif isinstance(k,str):   return attrgetter(k)\n",
+    "    elif isinstance(k,tuple): return lambda x: tuple(_conv_key(o)(x) for o in k)\n",
+    "    return k\n",
+    "\n",
     "def groupby(x, key, val=noop):\n",
     "    \"Like `itertools.groupby` but doesn't need to be sorted, and isn't lazy, plus some extensions\"\n",
-    "    if   isinstance(key,int): key = itemgetter(key)\n",
-    "    elif isinstance(key,str): key = attrgetter(key)\n",
-    "    if   isinstance(val,int): val = itemgetter(val)\n",
-    "    elif isinstance(val,str): val = attrgetter(val)\n",
+    "    key = _conv_key(key)\n",
+    "    val = _conv_key(val)\n",
     "    res = {}\n",
     "    for o in x: res.setdefault(key(o), []).append(val(o))\n",
     "    return res"
@@ -3625,7 +3629,39 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Here's an example of how to *invert* a grouping, using an `int` as `key` (which uses `itemgetter`; passing a `str` will use `attrgetter`), and using a `val` function:"
+    "You can use an `int` as `key` or `val` (which uses `itemgetter`; passing a `str` will use `attrgetter`), eg:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "test_eq(groupby('aa ab bb'.split(), 0), {'a':['aa','ab'], 'b':['bb']})"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "...and you can use a tuple as `key` or `val` (which creates a tuple from the provided keys or vals), eg:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "test_eq(groupby('aaa abc bba'.split(), 0, (1,2)), {'a':[('a','a'),('b','c')], 'b':[('b','a')]})"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Here's an example of how to *invert* a grouping, and using a `val` function:"
    ]
   },
   {