PDF

PDF 处理指南

概览

本技能覆盖常见 PDF 工作流（Python + 命令行）。
若要填写 PDF 表单，请额外阅读 forms.md；更深入的扩展能力可看 reference.md。

快速开始

from pypdf import PdfReader, PdfWriter

reader = PdfReader("document.pdf")
print(f"Pages: {len(reader.pages)}")

text = ""
for page in reader.pages:
    text += page.extract_text()

Python 库

pypdf（基础结构处理）

合并

from pypdf import PdfWriter, PdfReader

writer = PdfWriter()
for pdf_file in ["doc1.pdf", "doc2.pdf", "doc3.pdf"]:
    reader = PdfReader(pdf_file)
    for page in reader.pages:
        writer.add_page(page)

with open("merged.pdf", "wb") as output:
    writer.write(output)

拆分

reader = PdfReader("input.pdf")
for i, page in enumerate(reader.pages):
    writer = PdfWriter()
    writer.add_page(page)
    with open(f"page_{i+1}.pdf", "wb") as output:
        writer.write(output)

元数据

reader = PdfReader("document.pdf")
meta = reader.metadata
print(meta.title, meta.author, meta.subject, meta.creator)

旋转页面

reader = PdfReader("input.pdf")
writer = PdfWriter()

page = reader.pages[0]
page.rotate(90)
writer.add_page(page)

with open("rotated.pdf", "wb") as output:
    writer.write(output)

pdfplumber（文本/表格抽取）

文本抽取

import pdfplumber

with pdfplumber.open("document.pdf") as pdf:
    for page in pdf.pages:
        print(page.extract_text())

表格抽取

with pdfplumber.open("document.pdf") as pdf:
    for i, page in enumerate(pdf.pages):
        tables = page.extract_tables()
        for j, table in enumerate(tables):
            print(f"Table {j+1} on page {i+1}:")
            for row in table:
                print(row)

进阶：多表拼接

import pandas as pd
import pdfplumber

all_tables = []
with pdfplumber.open("document.pdf") as pdf:
    for page in pdf.pages:
        for table in page.extract_tables():
            if table:
                all_tables.append(pd.DataFrame(table[1:], columns=table[0]))

if all_tables:
    pd.concat(all_tables, ignore_index=True).to_excel("extracted_tables.xlsx", index=False)

reportlab（新建 PDF）

基础单页

from reportlab.lib.pagesizes import letter
from reportlab.pdfgen import canvas

c = canvas.Canvas("hello.pdf", pagesize=letter)
width, height = letter

c.drawString(100, height - 100, "Hello World!")
c.drawString(100, height - 120, "This is a PDF created with reportlab")
c.line(100, height - 140, 400, height - 140)
c.save()

多页文档

from reportlab.lib.pagesizes import letter
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, PageBreak
from reportlab.lib.styles import getSampleStyleSheet

doc = SimpleDocTemplate("report.pdf", pagesize=letter)
styles = getSampleStyleSheet()
story = []

story.append(Paragraph("Report Title", styles["Title"]))
story.append(Spacer(1, 12))
story.append(Paragraph("This is the body of the report. " * 20, styles["Normal"]))
story.append(PageBreak())
story.append(Paragraph("Page 2", styles["Heading1"]))
story.append(Paragraph("Content for page 2", styles["Normal"]))

doc.build(story)

下标/上标（关键）

不要直接用 Unicode 下标/上标字符（在默认字体里容易显示为黑方块）。
用 Paragraph 的标记语法：

from reportlab.platypus import Paragraph
from reportlab.lib.styles import getSampleStyleSheet

styles = getSampleStyleSheet()
chemical = Paragraph("H<sub>2</sub>O", styles["Normal"])
squared = Paragraph("x<super>2</super> + y<super>2</super>", styles["Normal"])

命令行工具

pdftotext

pdftotext input.pdf output.txt
pdftotext -layout input.pdf output.txt
pdftotext -f 1 -l 5 input.pdf output.txt

qpdf

qpdf --empty --pages file1.pdf file2.pdf -- merged.pdf
qpdf input.pdf --pages . 1-5 -- pages1-5.pdf
qpdf input.pdf output.pdf --rotate=+90:1
qpdf --password=mypassword --decrypt encrypted.pdf decrypted.pdf

pdftk（若环境可用）

pdftk file1.pdf file2.pdf cat output merged.pdf
pdftk input.pdf burst
pdftk input.pdf rotate 1east output rotated.pdf

常见任务模板

扫描版 OCR

import pytesseract
from pdf2image import convert_from_path

images = convert_from_path("scanned.pdf")
text = ""
for i, image in enumerate(images):
    text += f"Page {i+1}:\n"
    text += pytesseract.image_to_string(image)
    text += "\n\n"

print(text)

加水印

from pypdf import PdfReader, PdfWriter

watermark = PdfReader("watermark.pdf").pages[0]
reader = PdfReader("document.pdf")
writer = PdfWriter()

for page in reader.pages:
    page.merge_page(watermark)
    writer.add_page(page)

with open("watermarked.pdf", "wb") as output:
    writer.write(output)

抽取图片

pdfimages -j input.pdf output_prefix

加密

from pypdf import PdfReader, PdfWriter

reader = PdfReader("input.pdf")
writer = PdfWriter()
for page in reader.pages:
    writer.add_page(page)

writer.encrypt("userpassword", "ownerpassword")
with open("encrypted.pdf", "wb") as output:
    writer.write(output)

快速索引

下一步

• 进阶技巧看 reference.md
• 表单填写严格按 forms.md