python - 使用正则表达式从 PDF 原始文本中提取子字符串

Question

我试图从 pdf 文档中提取具有罗马索引的小节。

例如，这是文档的一部分，

\n1.1\n \nSCOPE\n \nThis PTS specifies the\n \nrequirements \nand recommendations for Classification, Verification \n\nFunct\nions.\n \nThe scope includes the following:\n \ni.\n \nSemi\n-\nquantitative SIL classification\n \nii.\n \nSpurious trip analysis\n \niii.\n \nProbabilistic and architectural SIL verification\n \niv.\n \nRecommendations\n \nfor SIL gap closure'

我想要的只是下面:

This PTS specifies the\n \nrequirements \nand recommendations for Classification, Verification \n\nFunct\nions.\n \nThe scope includes the following:\n \ni.\n \nSemi\n-\nquantitative SIL classification\n \nii.\n \nSpurious trip analysis\n \niii.\n \nProbabilistic and architectural SIL verification\n \niv.\n \nRecommendations\n \nfor SIL gap closure

我需要罗马索引前的句子以及罗马索引内的内容。

但是，也有像下面这样的情况

3.1.3\n \nDo\nc\numentation\n \nrequired\n \nT\nh\ne\n \nl\nat\ne\ns\nt\n \nissue\n \nof\n \nt\nh\ne\n \nf\no\nllo\nw\ni\nng\n \ndocume\nn\nts\n \nshall\n \nbe\n \nav\na\nilab\nl\ne\n \nto\n \nthe\n \nte\na\nm\n \np\ne\nrf\no\nrm\ni\nng\n \nt\nh\ne \nc\nl\nass\ni\nf\ni\ncati\no\nn:\n \ni.\n \nMandatory reference document\n \na)\n \nCause and effect matrices (CEM)\n \nb)\n \nPiping and Instrument Diagram (P&ID) or Process and utility engineering \nflow schemes (PEFS)\n \nc)\n \nHAZOP report\n \nd)\n \nIPF reliability data\n \nii.\n \nOther reference document\n \na)\n \nProcess Flow Diagram (PFD) or Process Fl\now Scheme (PFS)\n \nb)\n \nPlant layout drawing\n \nc)\n \nProcess safeguarding flow schemes (PSFS)\n \nd)\n \nControl narratives\n \ne)\n \nInterlocks/ ESD logic diagram\n \nf)\n \nEquipment layout diagram\n \ng)\n \nMaintenance and Inspection Data\n \nh)\n \nPlant historian data\n \n \nT\nh\ne\n \nl\ni\ns\nt\n \na\nb\no\nve\n \nis\n \nn\no\nt\n \ne\nx\nh\na\nu\nsti\nv\ne. Any\n \not\nh\ne\nr\n \ndo\nc\nu\nm\ne\nn\nt\ns\n/ \nd\nr\na\nw\nin\ng\ns\n \nreq\nu\nir\ne\nd\n \nf\no\nr\n \nt\nhe \nc\nom\np\nletion\n \no\nf the\n \nIPF\n \ns\nt\nu\nd\ny\n \ns\nh\na\nll\n \nbe\n \nf\nu\nr\nn\nished\n \nas\n \na\nn\nd\n \nw\nhen\n \nre\nq\nui\nr\ne\nd\n.\n \n

我已将 pdf 转换为原始文本，并成功提取了文档的部分内容。

regx = re.compile( '\.\n \n.+?:\n \n',re.DOTALL)
find = str(txt)
indexhead.append((regx.findall(find)))

上面的代码只能提取标题，不能提取罗马字索引

.\n \nThe scope includes the following:\n \n

我正在尝试根据模式进行提取，但我想也许一些条件规则可能会有所帮助。

Answer 1

如果我对问题的理解正确，我们只想取出罗马索引，并获取整个段落，我们将从一个简单的表达式开始，例如:

.+[0-9]\.?.+?([A-Z][a-z].*)

然后，当出现新案例时，我们只需使用逻辑或并添加其他规则。

Demo

测试

# coding=utf8
# the above tag defines encoding for this document and is for Python 2.x compatibility

import re

regex = r".+[0-9]\.?.+?([A-Z][a-z].*)"

test_str = ("\\n1.1\\n \\nSCOPE\\n \\nThis PTS specifies the\\n \\nrequirements \\nand recommendations for Classification, Verification \\n\\nFunct\\nions.\\n \\nThe scope includes the following:\\n \\ni.\\n \\nSemi\\n-\\nquantitative SIL classification\\n \\nii.\\n \\nSpurious trip analysis\\n \\niii.\\n \\nProbabilistic and architectural SIL verification\\n \\niv.\\n \\nRecommendations\\n \\nfor SIL gap closure'\n\n"
    "3.1.3\\n \\nDo\\nc\\numentation\\n \\nrequired\\n \\nT\\nh\\ne\\n \\nl\\nat\\ne\\ns\\nt\\n \\nissue\\n \\nof\\n \\nt\\nh\\ne\\n \\nf\\no\\nllo\\nw\\ni\\nng\\n \\ndocume\\nn\\nts\\n \\nshall\\n \\nbe\\n \\nav\\na\\nilab\\nl\\ne\\n \\nto\\n \\nthe\\n \\nte\\na\\nm\\n \\np\\ne\\nrf\\no\\nrm\\ni\\nng\\n \\nt\\nh\\ne \\nc\\nl\\nass\\ni\\nf\\ni\\ncati\\no\\nn:\\n \\ni.\\n \\nMandatory reference document\\n \\na)\\n \\nCause and effect matrices (CEM)\\n \\nb)\\n \\nPiping and Instrument Diagram (P&ID) or Process and utility engineering \\nflow schemes (PEFS)\\n \\nc)\\n \\nHAZOP report\\n \\nd)\\n \\nIPF reliability data\\n \\nii.\\n \\nOther reference document\\n \\na)\\n \\nProcess Flow Diagram (PFD) or Process Fl\\now Scheme (PFS)\\n \\nb)\\n \\nPlant layout drawing\\n \\nc)\\n \\nProcess safeguarding flow schemes (PSFS)\\n \\nd)\\n \\nControl narratives\\n \\ne)\\n \\nInterlocks/ ESD logic diagram\\n \\nf)\\n \\nEquipment layout diagram\\n \\ng)\\n \\nMaintenance and Inspection Data\\n \\nh)\\n \\nPlant historian data\\n \\n \\nT\\nh\\ne\\n \\nl\\ni\\ns\\nt\\n \\na\\nb\\no\\nve\\n \\nis\\n \\nn\\no\\nt\\n \\ne\\nx\\nh\\na\\nu\\nsti\\nv\\ne. Any\\n \\not\\nh\\ne\\nr\\n \\ndo\\nc\\nu\\nm\\ne\\nn\\nt\\ns\\n/ \\nd\\nr\\na\\nw\\nin\\ng\\ns\\n \\nreq\\nu\\nir\\ne\\nd\\n \\nf\\no\\nr\\n \\nt\\nhe \\nc\\nom\\np\\nletion\\n \\no\\nf the\\n \\nIPF\\n \\ns\\nt\\nu\\nd\\ny\\n \\ns\\nh\\na\\nll\\n \\nbe\\n \\nf\\nu\\nr\\nn\\nished\\n \\nas\\n \\na\\nn\\nd\\n \\nw\\nhen\\n \\nre\\nq\\nui\\nr\\ne\\nd\\n.\\n \\n")

subst = "\\1"

# You can manually specify the number of replacements by changing the 4th argument
result = re.sub(regex, subst, test_str, 0, re.MULTILINE)

if result:
    print (result)

# Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

正则表达式

如果不需要此表达式，可以在 regex101.com 中对其进行修改/更改.

正则表达式电路

jex.im可视化正则表达式: