Estrazione di testo da un file PDF utilizzando Python

Question

Sto cercando di estrarre il testo incluso nel file PDF this utilizzando Python.

sto usando il modulo PyPDF2, e hanno il seguente script:

import PyPDF2 
pdf_file = open('sample.pdf') 
read_pdf = PyPDF2.PdfFileReader(pdf_file) 
number_of_pages = read_pdf.getNumPages() 
page = read_pdf.getPage(0) 
page_content = page.extractText() 
print page_content 

Quando eseguo il codice, ottengo il seguente output, che è diverso da quello incluso nel documento PDF:

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

Come posso estrarre il testo come è nel documento PDF?

Grazie.

Answer 1

È possibile utilizzare il tempo dimostrato xPDF e gli strumenti derivati ​​per estrarre il testo invece che pyPDF2 sembra avere various issues con l'estrazione del testo ancora.

La risposta lunga è che ci sono molte varianti come un testo è codificato all'interno PDF e che si può richiedere alla stringa PDF decodificato stesso, allora potrebbe essere necessario mappare con CMAP, quindi potrebbe essere necessario analizzare le distanza tra le parole e le lettere ecc.

Nel caso in cui il PDF sia danneggiato (ad esempio, se viene visualizzato il testo corretto ma quando si copia fornisce dati inutili) ed è necessario estrarre testo, è consigliabile convertire PDF in immagine (utilizzando ImageMagik) e quindi utilizzare Tesseract per ottenere il testo dall'immagine usando OCR.

Answer 2

Guardate questo codice:

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

L'output è:

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

Utilizzando lo stesso codice per leggere un PDF da 201308FCR.pdf uscita .La è normale.

sua documentation spiega perché:

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. 
    """ 

Answer 3

Usa Textract.

• http://textract.readthedocs.io/en/latest/
• https://github.com/deanmalmgren/textract

Esso supporta molti tipi di file, tra cui PDF

import textract 
text = textract.process("path/to/file.extension") 

Answer 4

È possibile utilizzare PDFtoText https://github.com/jalan/pdftotext

PDF in testo mantiene formato testo indentatio n, non importa se hai tavoli.

Answer 5

Era alla ricerca di una soluzione semplice da utilizzare per python 3.xe windows.Non sembra essere il sostegno di textract, che è un peccato, ma se siete alla ricerca di una soluzione semplice per Windows/Python 3 cassa il pacchetto tika, davvero semplice per i PDF lettura

from tika import parser 

raw = parser.from_file('sample.pdf') 
print(raw['content']) 

Answer 6

sto aggiungendo il codice per ottenere questo risultato: si sta lavorando bene per me:

# 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)