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MarkdownHeaderTextSplitter

動機

許多聊天或問答應用程式都涉及在嵌入和向量儲存之前對輸入文件進行分塊。

Pinecone 的這些註釋提供了一些有用的提示：

When a full paragraph or document is embedded, the embedding process considers both the overall context and the relationships between the sentences and phrases within the text. This can result in a more comprehensive vector representation that captures the broader meaning and themes of the text.

當要對完整的段落或文件進行 embedding 時，embedding 過程會考慮整體上下文以及文本中句子和短語之間的關係。因為這樣可以產生更全面的向量表示，捕獲文本的會包佝了更廣泛的含義和主題。

如前所述，分塊通常旨在將具有共同上下文的文字放在一起。考慮到這一點，我們可能希望特別尊重文檔本身的結構。例如，Markdown 文件是按標題組織的。在特定標頭組中建立區塊是一個直觀的想法。為了解決這個挑戰，我們可以使用 MarkdownHeaderTextSplitter。這將按一組指定的標頭拆分 Markdown 文件。

例如，如果我們想分割這個 markdown：

md = '# Foo\n\n ## Bar\n\nHi this is Jim  \nHi this is Joe\n\n ## Baz\n\n Hi this is Molly'

我們可以指定要拆分的標頭：

[("#", "Header 1"),("##", "Header 2")]

內容按通用標題分組或分割：

{'content': 'Hi this is Jim  \nHi this is Joe', 'metadata': {'Header 1': 'Foo', 'Header 2': 'Bar'}}
{'content': 'Hi this is Molly', 'metadata': {'Header 1': 'Foo', 'Header 2': 'Baz'}}

讓我們來看看下面的一些例子。

from langchain.text_splitter import MarkdownHeaderTextSplitter

API Reference:

markdown_document = "# Foo\n\n    ## Bar\n\nHi this is Jim\n\nHi this is Joe\n\n ### Boo \n\n Hi this is Lance \n\n ## Baz\n\n Hi this is Molly"

headers_to_split_on = [
    ("#", "Header 1"),
    ("##", "Header 2"),
    ("###", "Header 3"),
]

markdown_splitter = MarkdownHeaderTextSplitter(headers_to_split_on=headers_to_split_on)

md_header_splits = markdown_splitter.split_text(markdown_document)

print(md_header_splits)

結果:

[Document(page_content='Hi this is Jim  \nHi this is Joe', metadata={'Header 1': 'Foo', 'Header 2': 'Bar'}),
    Document(page_content='Hi this is Lance', metadata={'Header 1': 'Foo', 'Header 2': 'Bar', 'Header 3': 'Boo'}),
    Document(page_content='Hi this is Molly', metadata={'Header 1': 'Foo', 'Header 2': 'Baz'})]

print(type(md_header_splits[0]))

結果:

langchain.schema.Document

在每個 Markdown 群組中，我們可以應用我們想要的任何文字分割器。

markdown_document = "# Intro \n\n    ## History \n\n Markdown[9] is a lightweight markup language for creating formatted text using a plain-text editor. John Gruber created Markdown in 2004 as a markup language that is appealing to human readers in its source code form.[9] \n\n Markdown is widely used in blogging, instant messaging, online forums, collaborative software, documentation pages, and readme files. \n\n ## Rise and divergence \n\n As Markdown popularity grew rapidly, many Markdown implementations appeared, driven mostly by the need for \n\n additional features such as tables, footnotes, definition lists,[note 1] and Markdown inside HTML blocks. \n\n #### Standardization \n\n From 2012, a group of people, including Jeff Atwood and John MacFarlane, launched what Atwood characterised as a standardisation effort. \n\n ## Implementations \n\n Implementations of Markdown are available for over a dozen programming languages."

headers_to_split_on = [
    ("#", "Header 1"),
    ("##", "Header 2"),
]

# MD splits
markdown_splitter = MarkdownHeaderTextSplitter(headers_to_split_on=headers_to_split_on)
md_header_splits = markdown_splitter.split_text(markdown_document)

# Char-level splits
from langchain.text_splitter import RecursiveCharacterTextSplitter

chunk_size = 250
chunk_overlap = 30
text_splitter = RecursiveCharacterTextSplitter(
    chunk_size=chunk_size, chunk_overlap=chunk_overlap
)

# Split
splits = text_splitter.split_documents(md_header_splits)

print(splits)

API Reference:

[Document(page_content='Markdown[9] is a lightweight markup language for creating formatted text using a plain-text editor. John Gruber created Markdown in 2004 as a markup language that is appealing to human readers in its source code form.[9]', metadata={'Header 1': 'Intro', 'Header 2': 'History'}),
    Document(page_content='Markdown is widely used in blogging, instant messaging, online forums, collaborative software, documentation pages, and readme files.', metadata={'Header 1': 'Intro', 'Header 2': 'History'}),
    Document(page_content='As Markdown popularity grew rapidly, many Markdown implementations appeared, driven mostly by the need for  \nadditional features such as tables, footnotes, definition lists,[note 1] and Markdown inside HTML blocks.  \n#### Standardization', metadata={'Header 1': 'Intro', 'Header 2': 'Rise and divergence'}),
    Document(page_content='#### Standardization  \nFrom 2012, a group of people, including Jeff Atwood and John MacFarlane, launched what Atwood characterised as a standardisation effort.', metadata={'Header 1': 'Intro', 'Header 2': 'Rise and divergence'}),
    Document(page_content='Implementations of Markdown are available for over a dozen programming languages.', metadata={'Header 1': 'Intro', 'Header 2': 'Implementations'})]