问使用Python仅从PDF中提取特定文本

EN

import PyPDF2


pdfFileObj = open('test.pdf', 'rb')
pdfReader = PyPDF2.PdfFileReader(pdfFileObj)

fields = pdfReader.getFormTextFields()

print(fields["Invoice ID"])
print(fields["Issue Date"])
print(fields["Subject"])
print(fields["Amount Due"])

import PyPDF2
import re
import os

from io import StringIO

from pdfminer.converter import TextConverter
from pdfminer.layout import LAParams
from pdfminer.pdfdocument import PDFDocument
from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter
from pdfminer.pdfpage import PDFPage
from pdfminer.pdfparser import PDFParser


def parse_pdf_by_regex_2(filename: str) -> dict:
    output_string = StringIO()
    with open(filename, 'rb') as in_file:
        parser = PDFParser(in_file)
        doc = PDFDocument(parser)
        rsrcmgr = PDFResourceManager()
        device = TextConverter(rsrcmgr, output_string, laparams=LAParams())
        interpreter = PDFPageInterpreter(rsrcmgr, device)
        for page in PDFPage.create_pages(doc):
            interpreter.process_page(page)

    regex_invoice_no = re.compile(r"Invoice No.:\s*(\w+)\s")
    regex_order_no = re.compile(r"IRN:\s*(\d+)")
    regex_due_date = re.compile(r"Due Date: (\d{2}\.\d{2}\.\d{4})")
    regex_total_due = re.compile(r"([\d,.]+) \n\nTotal Invoice Value\(in words\)")

    try:
        return {"invoice_id": re.search(regex_invoice_no, output_string.getvalue()).group(1),
                "issue_date": re.search(regex_due_date, output_string.getvalue()).group(1),
                "subject": re.search(regex_order_no, output_string.getvalue()).group(1),
                "amount": re.search(regex_total_due, output_string.getvalue()).group(1)}

    except AttributeError as err:
        print("Not all elements have been found")
        return {}


def parse_pdf_by_form_fields(filename: str) -> dict:
    with open(filename, 'rb') as file:
        pdf_reader = PyPDF2.PdfFileReader(file)
        try:
            fields = pdf_reader.getFormTextFields()
        except TypeError as err:
            # print("No FormFields available")
            return {}

    try:
        # You can also check if onyly missing some values, maybe this can happen, but this is up to your data
        return {"invoice_id": fields["Invoice ID"],
                "issue_date": fields["Issue Date"],
                "subject": fields["Subject"],
                "amount": fields["Amount Due"]}
    except KeyError as err:
        # print(f"Key not found: '{err.args[0]}'")
        return {}


def parse_pdf_by_regex(filename: str) -> dict:
    with open(filename, 'rb') as file:
        pdf_reader = PyPDF2.PdfFileReader(file)
        text_data = ""
        for page_no in range(pdf_reader.getNumPages()):
            text_data += pdf_reader.getPage(page_no).extractText()

    regex_invoice_no = re.compile(r"Invoice Number\s*(INV-\d+)")
    regex_order_no = re.compile(r"Order Number(\d+)")
    regex_due_date = re.compile(r"Due Date(\S+ \d{1,2}, \d{4})")
    regex_total_due = re.compile(r"Total Due(\$\d+\.\d{1,2})")

    try:
        return {"invoice_id": re.search(regex_invoice_no, text_data).group(1),
                "issue_date": re.search(regex_due_date, text_data).group(1),
                "subject": re.search(regex_order_no, text_data).group(1),
                "amount": re.search(regex_total_due, text_data).group(1)}

    except AttributeError as err:
        # print("Not all elements have been found")
        return {}


def parse_pdf(filename: str) -> dict:
    # Hint: ':=' is available since pythoon 3.8
    if data := parse_pdf_by_form_fields(filename=fname):
        return data
    elif data := parse_pdf_by_regex(filename=fname):
        return data
    elif data := parse_pdf_by_regex_2(filename=fname):
        return data
    else:
        print("No data found")
        return {}


if __name__ == '__main__':
    for fname in os.listdir("."):
        if fname.startswith("testfile"):
            print(f"check {fname}")
            print(parse_pdf(filename=fname))