How to Insert One PDF into Another Using PyPDF2 in Python

Preface: The author, a Python enthusiast, learned PDF handling from a book and was asked a PDF processing question in a group.

Idea

Three possible approaches: split PDFs then merge, try merge inserting at a specific page, or add pages one by one and save as a new file.

Solution

The third approach was chosen as the simplest. It uses the PyPDF2 library, which must be installed via pip install PyPDF2. PyPDF2 can split, merge, encrypt, and extract PDFs.

Example code:

from PyPDF2 import PdfFileReader, PdfFileWriter

pdf_file1 = PdfFileReader("dogs_0.pdf")  # PDF to insert
pdf_file2 = PdfFileReader("python介绍.pdf")  # Target PDF
new_file = PdfFileWriter()

# Insert pdf_file1 after the second page of pdf_file2
new_file.addPage(pdf_file2.getPage(0))
new_file.addPage(pdf_file2.getPage(1))
new_file.addPage(pdf_file1.getPage(0))
new_file.addPage(pdf_file2.getPage(2))

with open("merged_file.pdf", "wb") as f:
    new_file.write(f)

Comments explain each step; for many pages, a loop can be used to avoid repetitive code.

Conclusion

The article demonstrates solving a real PDF split‑and‑merge problem with PyPDF2, highlighting its powerful features and helping readers deepen their understanding of the library.