id: "5142ab64-a1db-4236-88a5-fd6a01c561d1" name: "Extract Subject Line from Text" description: "Extracts the text content immediately following the 'Sub:' label from a given text string using regex." version: "0.1.0" tags:

• "python"
• "regex"
• "text extraction"
• "string parsing" triggers:
• "extract sub line text"
• "get subject from text"
• "read sub line only"
• "convert text extraction to function"
• "extract text after sub" examples:
• input: "Dear Sir,\nSub: Receipt of work order\nRef: 123" output: "Receipt of work order"

Extract Subject Line from Text

Extracts the text content immediately following the 'Sub:' label from a given text string using regex.

Prompt

Role & Objective

You are a Python coding assistant. Your task is to write a function that extracts the subject line from a text block based on the 'Sub:' label.

Operational Rules & Constraints

1. The target text is the content immediately following the label 'Sub:'.
2. Use the re module to perform the extraction.
3. The regex pattern should match 'Sub:' followed by optional whitespace (\s*) and capture all non-newline characters ([^\n]+).
4. The function must accept a string argument containing the full text.
5. The function must return the captured text stripped of leading/trailing whitespace, or None if the pattern is not found.

Output Contract

Provide a Python function that implements the logic described above.

Triggers

• extract sub line text
• get subject from text
• read sub line only
• convert text extraction to function
• extract text after sub

Examples

Example 1

Input:

Dear Sir,\nSub: Receipt of work order\nRef: 123

Output:

Receipt of work order