Directory loader for bulk documents in LangChain

Introduction

A directory loader helps you quickly load many documents from a folder all at once. It saves time by handling multiple files together instead of one by one.

You have a folder full of text files you want to process together.

You want to read many PDFs or documents from a directory for analysis.

You need to prepare a large set of documents for a language model.

You want to automate loading all files in a folder without manual steps.

Syntax

LangChain

from langchain.document_loaders import DirectoryLoader

loader = DirectoryLoader('path/to/folder', glob='**/*.txt')
documents = loader.load()

The DirectoryLoader takes a folder path and an optional glob pattern to select file types.

The load() method reads all matching files and returns a list of documents.

Examples

This loads all PDF files inside 'data/docs' and its subfolders.

LangChain

from langchain.document_loaders import DirectoryLoader

loader = DirectoryLoader('data/docs', glob='**/*.pdf')
docs = loader.load()

This loads all Markdown files directly inside the 'notes' folder.

LangChain

loader = DirectoryLoader('notes', glob='*.md')
docs = loader.load()

This loads all files in 'articles' folder with default pattern (usually all files).

LangChain

loader = DirectoryLoader('articles')
docs = loader.load()

Sample Program

This example loads all text files from the 'my_documents' folder and prints how many were loaded. It also shows a preview of the first document's content.

LangChain

from langchain.document_loaders import DirectoryLoader

# Create a loader for all text files in 'my_documents'
loader = DirectoryLoader('my_documents', glob='**/*.txt')

# Load all documents
documents = loader.load()

# Print the number of documents loaded
print(f"Loaded {len(documents)} documents.")

# Print the first 100 characters of the first document
if documents:
    print("First document preview:")
    print(documents[0].page_content[:100])

Important Notes

Make sure the folder path is correct and accessible.

The glob pattern helps filter file types, like '*.txt' or '**/*.pdf'.

Documents are returned as a list of objects with a page_content attribute holding the text.

Summary

DirectoryLoader loads many files from a folder at once.

Use glob to pick specific file types.

Call load() to get all documents as a list.

Practice

1. What is the main purpose of the DirectoryLoader in Langchain?

easy

A. To convert documents into text format

B. To save documents to a directory

C. To load multiple documents from a folder at once

D. To create a new directory for documents

Solution

1. Step 1: Understand DirectoryLoader's role

   The DirectoryLoader is designed to read many files from a folder in one go.

2. Step 2: Compare options with this role

   Only To load multiple documents from a folder at once describes loading multiple documents from a folder, matching DirectoryLoader's purpose.

3. Final Answer:

   To load multiple documents from a folder at once -> Option C

4. Quick Check:

   DirectoryLoader loads many files = A [OK]

Hint: DirectoryLoader reads many files from a folder at once [OK]

Common Mistakes:

• Confusing loading with saving files
• Thinking it converts file formats
• Assuming it creates directories

2. Which of the following is the correct way to specify a glob pattern to load only text files using DirectoryLoader?

easy

A. glob='*.txt'

B. glob='text/*'

C. glob='**/*.doc'

D. glob='*.pdf'

Solution

1. Step 1: Understand glob pattern for text files

   The pattern '*.txt' matches all files ending with .txt in the directory.

2. Step 2: Evaluate each option

   glob='*.txt' correctly uses '*.txt' to select text files. Others select different or incorrect file types.

3. Final Answer:

   glob='*.txt' -> Option A

4. Quick Check:

   Use '*.txt' to pick text files [OK]

Hint: Use '*.txt' to select text files with glob [OK]

Common Mistakes:

• Using folder names instead of file patterns
• Using wrong file extensions
• Confusing recursive patterns with simple glob

3. Given the code snippet:

loader = DirectoryLoader('docs', glob='*.md')
docs = loader.load()

What will docs contain?

medium

A. A list of all markdown (.md) documents in the 'docs' folder

B. A single markdown document from the 'docs' folder

C. An error because glob pattern is incorrect

D. A list of all files in 'docs' regardless of extension

Solution

1. Step 1: Analyze DirectoryLoader usage

   The DirectoryLoader is set to load files from 'docs' folder with glob '*.md', meaning markdown files only.

2. Step 2: Understand load() output

   The load() method returns a list of documents matching the glob pattern, so docs will be a list of markdown files.

3. Final Answer:

   A list of all markdown (.md) documents in the 'docs' folder -> Option A

4. Quick Check:

   load() returns list of files matching glob [OK]

Hint: load() returns list of files matching glob pattern [OK]

Common Mistakes:

• Expecting a single document instead of a list
• Assuming glob pattern is ignored
• Thinking load() returns file paths instead of documents

4. What is wrong with this code snippet?

loader = DirectoryLoader('files', glob='*.txt')
docs = loader.load

medium

A. Incorrect glob pattern for text files

B. Missing parentheses after load method call

C. DirectoryLoader requires absolute path only

D. load method does not exist in DirectoryLoader

Solution

1. Step 1: Check method call syntax

   The load method must be called with parentheses: load()

2. Step 2: Verify other parts

   Glob pattern '*.txt' is correct, DirectoryLoader accepts relative paths, and load() method exists.

3. Final Answer:

   Missing parentheses after load method call -> Option B

4. Quick Check:

   Method calls need () to execute [OK]

Hint: Remember to add () when calling methods [OK]

Common Mistakes:

• Forgetting parentheses on method calls
• Assuming glob pattern is wrong
• Thinking DirectoryLoader needs absolute paths

5. You want to load all PDF and text files from a folder named 'resources' using DirectoryLoader. Which code snippet correctly achieves this?

hard

A. loader = DirectoryLoader('resources', glob='*.pdf;*.txt')

B. loader = DirectoryLoader('resources')
docs = loader.load() # loads all files

C. loader = DirectoryLoader('resources', glob='*.pdf|*.txt')
docs = loader.load()

D. loader = DirectoryLoader('resources', glob='*.pdf')
loader2 = DirectoryLoader('resources', glob='*.txt')
docs = loader.load() + loader2.load()

Solution

1. Step 1: Understand glob pattern limitations

   DirectoryLoader's glob does not support multiple patterns separated by ';' or '|'.

2. Step 2: Check each option

   loader = DirectoryLoader('resources', glob='*.pdf') loader2 = DirectoryLoader('resources', glob='*.txt') docs = loader.load() + loader2.load() loads PDFs and text files separately and combines results, which works correctly. loader = DirectoryLoader('resources') docs = loader.load() # loads all files loads all files but not filtered. Options A and C use invalid glob patterns.

3. Final Answer:

   loader = DirectoryLoader('resources', glob='*.pdf') loader2 = DirectoryLoader('resources', glob='*.txt') docs = loader.load() + loader2.load() -> Option D

4. Quick Check:

   Use separate loaders for multiple file types [OK]

Hint: Use separate loaders and combine for multiple file types [OK]

Common Mistakes:

• Trying to use multiple patterns in one glob string
• Assuming glob supports ';' or '|' separators
• Loading all files without filtering