PDF text extraction retrieves usable data from documents whose contents are not already structured. A practical task might involve extracting recurring film-industry tables across several years before analyzing admissions, genres, or distributors. section 5.4 section 5.4.2
Choose an extraction approach by balancing scale, accuracy, privacy, cost, and automation:
- Copy a small amount of data manually when the task is limited and one-off. section 5.4.2
- Use a dedicated web or desktop tool when convenience or likely accuracy matters, while checking cost and privacy implications. section 5.4.2
- Use capabilities in an existing toolkit when repeated files require automation and scalability. section 5.4.2
- Inspect extracted tables, reshape them into data frames, standardize columns, combine years, and verify expected row counts. section 5.4.2
Extracting tables with Python
With pdfplumber, open a PDF, select a page, find its tables, extract their cells, and convert the result into a pandas DataFrame. A reusable function can process selected pages, return multiple tables, and optionally print them for inspection. Subsequent transformations can select relevant columns, rename fields, add a year, remove unwanted rows, concatenate yearly data, and save a CSV. section 5.4.2
Table 5.1 Comparing PDF extraction techniques
|
Option
|
Pros
|
Cons
|
|---|---|---|
|
Manually copying data from PDFs into Excel
|
• Quick for a small amount of data
|
• Cannot be automated
• Does not scale to more data
|
|
Dedicated PDF extraction tool, either web or desktop based
|
• Likely to be accurate
• Web-based tool requires no installation
|
• May not be free
• Privacy concerns if uploading files to the web
• Hard to automate
• May not scale to multiple files
|
|
Finding PDF capabilities in our current tool
|
• Allows automation and scales to many files
• No need to leave/change our preferred tools
|
• Current toolkit may not have such capabilities
• If there are few files and a one-off task, it might be quicker to extract data manually.
|
Compare manual copying, dedicated extraction tools, and existing-tool capabilities by accuracy, installation, privacy, automation, cost, and scalability. section 5.4.2
