DirectoryLoader slicing (#8994)

DirectoryLoader can now return a random sample of files in a directory.
Parameters added are:
sample_size
randomize_sample
sample_seed


@rlancemartin, @eyurtsev

---------

Co-authored-by: Andrew Oseen <amovfx@protonmail.com>
Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/langchain/langchain/document_loaders/directory.py

@@ -1,6 +1,7 @@
 """Load documents from a directory."""
 import concurrent
 import logging
+import random
 from pathlib import Path
 from typing import Any, List, Optional, Type, Union
 
@@ -39,6 +40,10 @@ class DirectoryLoader(BaseLoader):
         show_progress: bool = False,
         use_multithreading: bool = False,
         max_concurrency: int = 4,
+        *,
+        sample_size: int = 0,
+        randomize_sample: bool = False,
+        sample_seed: Union[int, None] = None,
     ):
         """Initialize with a path to directory and how to glob over it.
 
@@ -55,6 +60,10 @@ class DirectoryLoader(BaseLoader):
             show_progress: Whether to show a progress bar. Defaults to False.
             use_multithreading: Whether to use multithreading. Defaults to False.
             max_concurrency: The maximum number of threads to use. Defaults to 4.
+            sample_size: The maximum number of files you would like to load from the
+                directory.
+            randomize_sample: Suffle the files to get a random sample.
+            sample_seed: set the seed of the random shuffle for reporoducibility.
         """
         if loader_kwargs is None:
             loader_kwargs = {}
@@ -68,6 +77,9 @@ class DirectoryLoader(BaseLoader):
         self.show_progress = show_progress
         self.use_multithreading = use_multithreading
         self.max_concurrency = max_concurrency
+        self.sample_size = sample_size
+        self.randomize_sample = randomize_sample
+        self.sample_seed = sample_seed
 
     def load_file(
         self, item: Path, path: Path, docs: List[Document], pbar: Optional[Any]
@@ -107,6 +119,14 @@ class DirectoryLoader(BaseLoader):
         docs: List[Document] = []
         items = list(p.rglob(self.glob) if self.recursive else p.glob(self.glob))
 
+        if self.sample_size > 0:
+            if self.randomize_sample:
+                randomizer = (
+                    random.Random(self.sample_seed) if self.sample_seed else random
+                )
+                randomizer.shuffle(items)  # type: ignore
+            items = items[: min(len(items), self.sample_size)]
+
         pbar = None
         if self.show_progress:
             try: