下面是提取文本的最简单代码

代码:

# importing required modules
import PyPDF2

# creating a pdf file object
pdfFileObj = open('filename.pdf', 'rb')

# creating a pdf reader object
pdfReader = PyPDF2.PdfFileReader(pdfFileObj)

# printing number of pages in pdf file
print(pdfReader.numPages)

# creating a page object
pageObj = pdfReader.getPage(5)

# extracting text from page
print(pageObj.extractText())

# closing the pdf file object
pdfFileObj.close()

Pdfplumber是一个更好的从pdf中读取和提取数据的库。它还提供了读取表数据的方法，在经历了大量这样的库之后，pdfplumber最适合我。

请注意，它最适合机器编写的pdf，而不是扫描的pdf。

import pdfplumber
with pdfplumber.open(r'D:\examplepdf.pdf') as pdf:
first_page = pdf.pages[0]
print(first_page.extract_text())

看看PyPDF2<=1.26.0的代码:

import PyPDF2
pdf_file = open('sample.pdf', 'rb')
read_pdf = PyPDF2.PdfFileReader(pdf_file)
page = read_pdf.getPage(0)
page_content = page.extractText()
print page_content.encode('utf-8')

输出结果为:

!"#$%#$%&%$&'()*%+,-%./01'*23%4
5'%1$#26%3/%7/))/8%&)/26%8#3"%3"*%313/9#&)
%

使用相同的代码从201308FCR.pdf读取pdf .输出正常。

它的文档解释了原因:

def extractText(self):
    """
    Locate all text drawing commands, in the order they are provided in the
    content stream, and extract the text.  This works well for some PDF
    files, but poorly for others, depending on the generator used.  This will
    be refined in the future.  Do not rely on the order of text coming out of
    this function, as it will change if this function is made more
    sophisticated.
    :return: a unicode string object.
    """

我正在添加代码来实现这一点: 这对我来说很好:

# This works in python 3
# required python packages
# tabula-py==1.0.0
# PyPDF2==1.26.0
# Pillow==4.0.0
# pdfminer.six==20170720

import os
import shutil
import warnings
from io import StringIO

import requests
import tabula
from PIL import Image
from PyPDF2 import PdfFileWriter, PdfFileReader
from pdfminer.converter import TextConverter
from pdfminer.layout import LAParams
from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter
from pdfminer.pdfpage import PDFPage

warnings.filterwarnings("ignore")


def download_file(url):
    local_filename = url.split('/')[-1]
    local_filename = local_filename.replace("%20", "_")
    r = requests.get(url, stream=True)
    print(r)
    with open(local_filename, 'wb') as f:
        shutil.copyfileobj(r.raw, f)

    return local_filename


class PDFExtractor():
    def __init__(self, url):
        self.url = url

    # Downloading File in local
    def break_pdf(self, filename, start_page=-1, end_page=-1):
        pdf_reader = PdfFileReader(open(filename, "rb"))
        # Reading each pdf one by one
        total_pages = pdf_reader.numPages
        if start_page == -1:
            start_page = 0
        elif start_page < 1 or start_page > total_pages:
            return "Start Page Selection Is Wrong"
        else:
            start_page = start_page - 1

        if end_page == -1:
            end_page = total_pages
        elif end_page < 1 or end_page > total_pages - 1:
            return "End Page Selection Is Wrong"
        else:
            end_page = end_page

        for i in range(start_page, end_page):
            output = PdfFileWriter()
            output.addPage(pdf_reader.getPage(i))
            with open(str(i + 1) + "_" + filename, "wb") as outputStream:
                output.write(outputStream)

    def extract_text_algo_1(self, file):
        pdf_reader = PdfFileReader(open(file, 'rb'))
        # creating a page object
        pageObj = pdf_reader.getPage(0)

        # extracting extract_text from page
        text = pageObj.extractText()
        text = text.replace("\n", "").replace("\t", "")
        return text

    def extract_text_algo_2(self, file):
        pdfResourceManager = PDFResourceManager()
        retstr = StringIO()
        la_params = LAParams()
        device = TextConverter(pdfResourceManager, retstr, codec='utf-8', laparams=la_params)
        fp = open(file, 'rb')
        interpreter = PDFPageInterpreter(pdfResourceManager, device)
        password = ""
        max_pages = 0
        caching = True
        page_num = set()

        for page in PDFPage.get_pages(fp, page_num, maxpages=max_pages, password=password, caching=caching,
                                      check_extractable=True):
            interpreter.process_page(page)

        text = retstr.getvalue()
        text = text.replace("\t", "").replace("\n", "")

        fp.close()
        device.close()
        retstr.close()
        return text

    def extract_text(self, file):
        text1 = self.extract_text_algo_1(file)
        text2 = self.extract_text_algo_2(file)

        if len(text2) > len(str(text1)):
            return text2
        else:
            return text1

    def extarct_table(self, file):

        # Read pdf into DataFrame
        try:
            df = tabula.read_pdf(file, output_format="csv")
        except:
            print("Error Reading Table")
            return

        print("\nPrinting Table Content: \n", df)
        print("\nDone Printing Table Content\n")

    def tiff_header_for_CCITT(self, width, height, img_size, CCITT_group=4):
        tiff_header_struct = '<' + '2s' + 'h' + 'l' + 'h' + 'hhll' * 8 + 'h'
        return struct.pack(tiff_header_struct,
                           b'II',  # Byte order indication: Little indian
                           42,  # Version number (always 42)
                           8,  # Offset to first IFD
                           8,  # Number of tags in IFD
                           256, 4, 1, width,  # ImageWidth, LONG, 1, width
                           257, 4, 1, height,  # ImageLength, LONG, 1, lenght
                           258, 3, 1, 1,  # BitsPerSample, SHORT, 1, 1
                           259, 3, 1, CCITT_group,  # Compression, SHORT, 1, 4 = CCITT Group 4 fax encoding
                           262, 3, 1, 0,  # Threshholding, SHORT, 1, 0 = WhiteIsZero
                           273, 4, 1, struct.calcsize(tiff_header_struct),  # StripOffsets, LONG, 1, len of header
                           278, 4, 1, height,  # RowsPerStrip, LONG, 1, lenght
                           279, 4, 1, img_size,  # StripByteCounts, LONG, 1, size of extract_image
                           0  # last IFD
                           )

    def extract_image(self, filename):
        number = 1
        pdf_reader = PdfFileReader(open(filename, 'rb'))

        for i in range(0, pdf_reader.numPages):

            page = pdf_reader.getPage(i)

            try:
                xObject = page['/Resources']['/XObject'].getObject()
            except:
                print("No XObject Found")
                return

            for obj in xObject:

                try:

                    if xObject[obj]['/Subtype'] == '/Image':
                        size = (xObject[obj]['/Width'], xObject[obj]['/Height'])
                        data = xObject[obj]._data
                        if xObject[obj]['/ColorSpace'] == '/DeviceRGB':
                            mode = "RGB"
                        else:
                            mode = "P"

                        image_name = filename.split(".")[0] + str(number)

                        print(xObject[obj]['/Filter'])

                        if xObject[obj]['/Filter'] == '/FlateDecode':
                            data = xObject[obj].getData()
                            img = Image.frombytes(mode, size, data)
                            img.save(image_name + "_Flate.png")
                            # save_to_s3(imagename + "_Flate.png")
                            print("Image_Saved")

                            number += 1
                        elif xObject[obj]['/Filter'] == '/DCTDecode':
                            img = open(image_name + "_DCT.jpg", "wb")
                            img.write(data)
                            # save_to_s3(imagename + "_DCT.jpg")
                            img.close()
                            number += 1
                        elif xObject[obj]['/Filter'] == '/JPXDecode':
                            img = open(image_name + "_JPX.jp2", "wb")
                            img.write(data)
                            # save_to_s3(imagename + "_JPX.jp2")
                            img.close()
                            number += 1
                        elif xObject[obj]['/Filter'] == '/CCITTFaxDecode':
                            if xObject[obj]['/DecodeParms']['/K'] == -1:
                                CCITT_group = 4
                            else:
                                CCITT_group = 3
                            width = xObject[obj]['/Width']
                            height = xObject[obj]['/Height']
                            data = xObject[obj]._data  # sorry, getData() does not work for CCITTFaxDecode
                            img_size = len(data)
                            tiff_header = self.tiff_header_for_CCITT(width, height, img_size, CCITT_group)
                            img_name = image_name + '_CCITT.tiff'
                            with open(img_name, 'wb') as img_file:
                                img_file.write(tiff_header + data)

                            # save_to_s3(img_name)
                            number += 1
                except:
                    continue

        return number

    def read_pages(self, start_page=-1, end_page=-1):

        # Downloading file locally
        downloaded_file = download_file(self.url)
        print(downloaded_file)

        # breaking PDF into number of pages in diff pdf files
        self.break_pdf(downloaded_file, start_page, end_page)

        # creating a pdf reader object
        pdf_reader = PdfFileReader(open(downloaded_file, 'rb'))

        # Reading each pdf one by one
        total_pages = pdf_reader.numPages

        if start_page == -1:
            start_page = 0
        elif start_page < 1 or start_page > total_pages:
            return "Start Page Selection Is Wrong"
        else:
            start_page = start_page - 1

        if end_page == -1:
            end_page = total_pages
        elif end_page < 1 or end_page > total_pages - 1:
            return "End Page Selection Is Wrong"
        else:
            end_page = end_page

        for i in range(start_page, end_page):
            # creating a page based filename
            file = str(i + 1) + "_" + downloaded_file

            print("\nStarting to Read Page: ", i + 1, "\n -----------===-------------")

            file_text = self.extract_text(file)
            print(file_text)
            self.extract_image(file)

            self.extarct_table(file)
            os.remove(file)
            print("Stopped Reading Page: ", i + 1, "\n -----------===-------------")

        os.remove(downloaded_file)


# I have tested on these 3 pdf files
# url = "http://s3.amazonaws.com/NLP_Project/Original_Documents/Healthcare-January-2017.pdf"
url = "http://s3.amazonaws.com/NLP_Project/Original_Documents/Sample_Test.pdf"
# url = "http://s3.amazonaws.com/NLP_Project/Original_Documents/Sazerac_FS_2017_06_30%20Annual.pdf"
# creating the instance of class
pdf_extractor = PDFExtractor(url)

# Getting desired data out
pdf_extractor.read_pages(15, 23)

我在这里找到了一个解决方案PDFLayoutTextStripper

这很好，因为它可以保持原始PDF的布局。

它是用Java编写的，但我已经添加了一个网关来支持Python。

示例代码:

from py4j.java_gateway import JavaGateway

gw = JavaGateway()
result = gw.entry_point.strip('samples/bus.pdf')

# result is a dict of {
#   'success': 'true' or 'false',
#   'payload': pdf file content if 'success' is 'true'
#   'error': error message if 'success' is 'false'
# }

print result['payload']

示例输出PDFLayoutTextStripper:

你可以在这里看到更多细节Stripper with Python

你可以从这里下载tika-app-xxx.jar(最新)。

然后将这个.jar文件放在python脚本文件的同一文件夹中。

然后在脚本中插入如下代码:

import os
import os.path

tika_dir=os.path.join(os.path.dirname(__file__),'<tika-app-xxx>.jar')

def extract_pdf(source_pdf:str,target_txt:str):
    os.system('java -jar '+tika_dir+' -t {} > {}'.format(source_pdf,target_txt))

该方法的优点:

更少的依赖。单个.jar文件比python包更容易管理。

开始支持。位置source_pdf可以是任何类型文档的目录。(.doc， .html， .odt等)

最新的。tika-app.jar始终先于相关版本的tika python包发布。

稳定。它比PyPDF更加稳定和维护良好(由Apache提供支持)。

劣势:

一个无头小丑是必要的。