kindall的回答非常好。但是,由于后来(由梦想家)请求了一个工作代码示例,并且由于我今天遇到了同样的问题,所以我想添加一些注释。
pdf结构不统一;您可以依赖的东西很少,因此任何工作代码示例都不太可能适用于所有人。在这个答案中可以找到一个很好的解释。
正如 kindall 所解释的,您很可能需要探索您正在处理的 pdf。
像这样:
import sys
import PyPDF2 as pyPdf
"""Open your pdf"""
pdf = pyPdf.PdfFileReader(open(sys.argv[1], "rb"))
"""Explore the /PageLabels (if it exists)"""
try:
page_label_type = pdf.trailer["/Root"]["/PageLabels"]
print(page_label_type)
except:
print("No /PageLabel object")
"""Select the item that is most likely to contain the information you desire; e.g.
{'/Nums': [0, IndirectObject(42, 0)]}
here, we only have "/Num". """
try:
page_label_type = pdf.trailer["/Root"]["/PageLabels"]["/Nums"]
print(page_label_type)
except:
print("No /PageLabel object")
"""If you see a list, like
[0, IndirectObject(42, 0)]
get the correct item from it"""
try:
page_label_type = pdf.trailer["/Root"]["/PageLabels"]["/Nums"][1]
print(page_label_type)
except:
print("No /PageLabel object")
"""If you then have an indirect object, like
IndirectObject(42, 0)
use getObject()"""
try:
page_label_type = pdf.trailer["/Root"]["/PageLabels"]["/Nums"][1].getObject()
print(page_label_type)
except:
print("No /PageLabel object")
"""Now we have e.g.
{'/S': '/r', '/St': 21}
meaning roman numerals, starting with page 21, i.e. xxi. We can now also obtain the two variables directly."""
try:
page_label_type = pdf.trailer["/Root"]["/PageLabels"]["/Nums"][1].getObject()["/S"]
print(page_label_type)
start_page = pdf.trailer["/Root"]["/PageLabels"]["/Nums"][1].getObject()["/St"]
print(start_page)
except:
print("No /PageLabel object")
- 正如您从 ISO pdf 1.7 规范(此处的相关部分)中看到的那样,如何标记页面有很多可能性。作为一个简单的工作示例,请考虑这个脚本,它至少可以处理十进制(阿拉伯)和罗马数字:
脚本:
import sys
import PyPDF2 as pyPdf
def arabic_to_roman(arabic):
roman = ''
while arabic >= 1000:
roman += 'm'
arabic -= 1000
diffs = [900, 500, 400, 300, 200, 100, 90, 50, 40, 30, 20, 10, 9, 5, 4, 3, 2, 1]
digits = ['cm', 'd', 'cd', 'ccc', 'cc', 'c', 'xc', 'l', 'xl', 'xxx', 'xx', 'x', 'ix', 'v', 'iv', 'iii', 'ii', 'i']
for i in range(len(diffs)):
if arabic >= diffs[i]:
roman += digits[i]
arabic -= diffs[i]
return(roman)
def get_page_labels(pdf):
try:
page_label_type = pdf.trailer["/Root"]["/PageLabels"]["/Nums"][1].getObject()["/S"]
except:
page_label_type = "/D"
try:
page_start = pdf.trailer["/Root"]["/PageLabels"]["/Nums"][1].getObject()["/St"]
except:
page_start = 1
page_count = pdf.getNumPages()
##or, if you feel fancy, do:
#page_count = pdf.trailer["/Root"]["/Pages"]["/Count"]
page_stop = page_start + page_count
if page_label_type == "/D":
page_numbers = list(range(page_start, page_stop))
for i in range(len(page_numbers)):
page_numbers[i] = str(page_numbers[i])
elif page_label_type == '/r':
page_numbers_arabic = range(page_start, page_stop)
page_numbers = []
for i in range(len(page_numbers_arabic)):
page_numbers.append(arabic_to_roman(page_numbers_arabic[i]))
print(page_label_type)
print(page_start)
print(page_count)
print(page_numbers)
pdf = pyPdf.PdfFileReader(open(sys.argv[1], "rb"))
get_page_labels(pdf)