Merge PDF files

python

pdf-engineering

functions

best-practices

byAnton Shumikhin·Feb 28, 2025

Merge PDFs in Python using PyPDF2 with a seamless approach. Get the library using pip install PyPDF2, create a merger object, pile up files, and pen it down:

from PyPDF2 import PdfMerger

merger = PdfMerger()
# Who doesn't like a PDF party?
for pdf in ['file1.pdf', 'file2.pdf']:
    merger.append(pdf)  # Inviting PDFs to the party
merger.write("merged.pdf")  # The party photo album
merger.close()  # Bye, time to clean up

Three easy steps: import PdfMerger, make a append(pdf) loop, and write("merged.pdf"). It's as simple as driving a Tesla.

Nailing advanced merging

In the epic game of Thrones of PDF operations, libraries like PyPDF2, PyMuPDF, and pdfrw are your dragons. Let's ride them:

Page-by-page conquest with PyPDF2

Enjoy power over the fiefdom of page ranges using the pages keyword argument. Wage war on disorganization:

from PyPDF2 import PdfMerger

merger = PdfMerger()
# Selecting the fiercest pages for the fight
merger.append('file1.pdf', pages=(0, 3))  # We want the first three pages of file1.pdf
merger.append('file2.pdf', pages=(2, None))  # The fight starts from page 3 till the end in file2.pdf
merger.write('merged.pdf')
merger.close()  # Victory drink time

PyMuPDF: The dragon of high-performance merging

For merging faster than a Valyrian sword cut, saddle up PyMuPDF:

import fitz  # PyMuPDF, short and classy

pdf_writer = fitz.open()
for pdf in ['file1.pdf', 'file2.pdf']:
    pdf_document = fitz.open(pdf)
    pdf_writer.insert_pdf(pdf_document)
    pdf_document.close()  # Another one bites the dust
pdf_writer.save('merged.pdf')
pdf_writer.close()  # And it's a wrap

Conquering directories with a batch

When playing the game of thrones with directories, use your armies (os.listdir() or glob.glob()) for batch attacks:

import glob
from PyPDF2 import PdfMerger

pdf_files = glob.glob('*.pdf')
merger = PdfMerger()

for pdf in pdf_files:
    merger.append(pdf)  # Here comes my army

merger.write('directory_merged.pdf')
merger.close()  # Tell them Winter came for House Globs

Remember: 'rb' and 'wb' protect you from I/O white walkers. And close the castle gates (manage file closures) to avert resource leaks and dreaded data corruption.

Advanced methods to level up

Every professional Pythonist needs a few good grimoires up their sleeves:

PDFly casting spells

The pdfly cat command is an incantation for console wizards:

$ pdfly cat file1.pdf file2.pdf -o merged.pdf

Conjuring merge functions

Master the ancient art of spell-making by crafting your own merge function:

def merge_pdfs(file_list, output_name): 
    merger = PdfMerger()
    for pdf in file_list:
        merger.append(pdf)
    merger.write(output_name)
    merger.close()

file_names = ['file1.pdf', 'file2.pdf']
merge_pdfs(file_names, 'hogwarts_story.pdf')  # A magical story awaits

Safeguarding ancient knowledge

Practice defensive spellcasting (error handling) to protect your repository of PDF artifacts:

try:
    merge_pdfs(file_names, 'safe_hogwarts_story.pdf')
except Exception as e:
    print(f"Dementors attacked the script: {e}")  # Where's Harry when you need him?