Groupby and print capabilities

README.md

@@ -1,3 +1,8 @@
 # MORG Stream Library
 
-This python library allows for the handling of data in a stream format.
+This python library allows for the handling of data in a stream format.
+
+The library may be installed from Avalon with:
+```
+pip install git+https://git.icolotl.com/morgana/morgslib
+```

src/morgslib/morgslib.py

@@ -15,6 +15,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+from collections import defaultdict
 from typing import Any, Callable, Iterable, Iterator, Self, TypeVar, Generic
 
 T = TypeVar('T')
@@ -47,5 +48,14 @@ class Stream(Generic[T]):
     def first(self, fxn: Callable[[T], bool]) -> T | None:
         return next(filter(fxn, self.iter), None)
 
+    def groupby(self, fxn: Callable[[T], Tn]) -> Stream[tuple[Tn, list[T]]]:
+        out: defaultdict[Tn, list[T]] = defaultdict(list)
+        for item in self.iter:
+            out[fxn(item)].append(item)
+        return Stream(out.items())
+
     def to(self, fxn: Callable) -> Any:
-        return fxn(self.iter)
+        return fxn(self.iter)
+
+    def print(self, sep=","):
+        print(*self.iter, sep=sep)