python - 使用python通过正则表达式选择文本中的每个段落

Question

我用 python 读取 PDF，并想从中提取特定段落。为此，我使用 python 并尝试通过正则表达式进行选择。为了说明这种情况，这里有一个例子。

INTERNATIONAL MONETARY FUND            7\n\x0cBELGIUM\n\n\n\nPOLICY DISCUSSIONS—MAINTAINING THE REFORM\nMOMENTUM\n7.     The current recovery is an opportunity to strengthen the resilience and growth\npotential of the Belgian economy. The government's ability to deal with future shocks will depend\non whether it implements the right policies now while the economy continues to recover.\n\n\uf0b7   First, with public debt above 100 percent of GDP and only starting to come down, Belgium still\n    has a long way to go to rebuild buffers and achieve a more sustainable fiscal position. This will\n    require following through on plans to gradually move toward structural balance.\n\n\uf0b7   Second, with real GDP growth projected at only around 1½ percent for the foreseeable future,\n    further labor and product market reforms are needed to increase productivity growth, raise\n    potential output, and integrate vulnerable groups into the labor market.\n\n\uf0b7   Third, although the financial sector has recovered since the crisis and is generally sound, cyclical\n    vulnerabilities are rising and new challenges are emerging, suggesting the need for vigilance\n    and proactive policies.3\n\n8.      The government agreed last summer on a new package of measures related to\ntaxation, the labor market, and social benefits (Table 2 and Box 1). The most notable reform was\na reduction in Belgium's corporate income tax (CIT) rate from 34 percent to 25 percent, to be\nphased in over the next three years (SMEs will benefit from a reduced rate of 20 percent starting in\n2018). To compensate for the resulting revenue loss, the notional interest rate deduction (NID) was\nmodified to apply only to incremental corporate equity rather than to the total stock, and new anti-\ntax avoidance measures were introduced consistent with Belgium's EU obligations.4 Together, the\nmeasures are designed to enhance Belgium's competitiveness while preserving revenue neutrality.\n\n9.      Policy discussions focused on the importance of maintaining the reform momentum\nand not yielding to complacency. Achieving the balanced budget goal will require efforts at all\nlevels of government to make spending more efficient and safeguard revenues (Section A).\nA combination of policies and reforms could help raise productivity growth, including increasing\ninvestment in infrastructure and enhancing competition in services (Section B). To fully realize\nBelgium's employment potential, it will be critical to address the severe fragmentation of the labor\nmarket (Section C). To preserve financial stability, the authorities should address vulnerabilities in the\nmortgage market and carefully navigate the transition toward a European Banking Union (Section D).\n\n\n\n\n3\n A comprehensive assessment of Belgium's financial sector took place in 2017 under the Financial Sector\nAssessment Program (FSAP).\n4\n  The NID aims to neutralize the CIT treatment of debt and equity by supplementing the deductibility of interest with\na deduction that is the product of corporate equity and a notional interest rate.\n\n\n8

每个段落都以一个数字(一位或两位数字)开头，后跟一个点和三到七个空格。末尾由下一个双换行符 \n\n 组成，后跟一个数字(一位或两位数字)，最后跟一个点。请注意，这也应该作为下一个起点。在上面的例子中，我应该找到三个段落:

第一段:

7. The current recovery is an opportunity to strengthen the resilience and growth\npotential of the Belgian economy. The government's ability to deal with future shocks will depend\non whether it implements the right policies now while the economy continues to recover.\n\n\uf0b7 First, with public debt above 100 percent of GDP and only starting to come down, Belgium still\n has a long way to go to rebuild buffers and achieve a more sustainable fiscal position. This will\n require following through on plans to gradually move toward structural balance.\n\n\uf0b7 Second, with real GDP growth projected at only around 1½ percent for the foreseeable future,\n further labor and product market reforms are needed to increase productivity growth, raise\n potential output, and integrate vulnerable groups into the labor market.\n\n\uf0b7 Third, although the financial sector has recovered since the crisis and is generally sound, cyclical\n vulnerabilities are rising and new challenges are emerging, suggesting the need for vigilance\n and proactive policies.3\n\n

第二段:

8. The government agreed last summer on a new package of measures related to\ntaxation, the labor market, and social benefits (Table 2 and Box 1). The most notable reform was\na reduction in Belgium's corporate income tax (CIT) rate from 34 percent to 25 percent, to be\nphased in over the next three years (SMEs will benefit from a reduced rate of 20 percent starting in\n2018). To compensate for the resulting revenue loss, the notional interest rate deduction (NID) was\nmodified to apply only to incremental corporate equity rather than to the total stock, and new anti-\ntax avoidance measures were introduced consistent with Belgium's EU obligations.4 Together, the\nmeasures are designed to enhance Belgium's competitiveness while preserving revenue neutrality.\n\n

最后是第三个:

9. Policy discussions focused on the importance of maintaining the reform momentum\nand not yielding to complacency. Achieving the balanced budget goal will require efforts at all\nlevels of government to make spending more efficient and safeguard revenues (Section A).\nA combination of policies and reforms could help raise productivity growth, including increasing\ninvestment in infrastructure and enhancing competition in services (Section B). To fully realize\nBelgium's employment potential, it will be critical to address the severe fragmentation of the labor\nmarket (Section C). To preserve financial stability, the authorities should address vulnerabilities in the\nmortgage market and carefully navigate the transition toward a European Banking Union (Section D).\n\n\n\n\n3\n A comprehensive assessment of Belgium's financial sector took place in 2017 under the Financial Sector\nAssessment Program (FSAP).\n4\n The NID aims to neutralize the CIT treatment of debt and equity by supplementing the deductibility of interest with\na deduction that is the product of corporate equity and a notional interest rate.\n\n

我尝试使用以下正则表达式:r'(?m)[0-99].*[.] {3,7} (.*?)\n\n从头到尾都有选择一切的推理

1. (?m)[0-99].*[.] {3,7}:分别标识每一行的开头。
2. \n\n 指定结束。

但是，它没有找到任何东西。

Answer 1

[0-99]模式是错误的，因为它匹配 0 中的任何 1 位数字至9 。请参阅Why doesn't [01-12] range work as expected? 。 re.M ( (?m) ) 修改 ^和$ anchor ，但模式中两者都没有。

您可以使用

r'(?sm)^\d\d?\. {3,7}(.*?)(?=\n\n\d\d?\. |\Z)'

请参阅regex demo .

详细信息

• (?sm) -re.DOTALL和re.MULTILINE已启用选项
• ^ - 一行的开头
• \d\d? - 1 或 2 位数字( 0 到 99 )
• \. - 一个点
• <code> {3,7}</code> - 3 to 7 spaces (replace with [^\S\r\n]{3,7}` 匹配任何水平空白)
• (.*?) - 第 1 组:任意 0 个以上字符，尽可能少
• (?=\n\n\d\d?\. |\Z) - 一个位置，紧跟两个换行符 ( \n\n )，然后是 1 或 2 位数字 ( \d\d? ) 和一个点，后跟空格或 ( | ) 整个字符串的末尾 ( \Z )。

Python demo :

import re
s="INTERNATIONAL MONETARY FUND            7\n\x0cBELGIUM\n\n\n\nPOLICY DISCUSSIONS—MAINTAINING THE REFORM\nMOMENTUM\n7.     The current recovery is an opportunity to strengthen the resilience and growth\npotential of the Belgian economy. The government's ability to deal with future shocks will depend\non whether it implements the right policies now while the economy continues to recover.\n\n\uf0b7   First, with public debt above 100 percent of GDP and only starting to come down, Belgium still\n    has a long way to go to rebuild buffers and achieve a more sustainable fiscal position. This will\n    require following through on plans to gradually move toward structural balance.\n\n\uf0b7   Second, with real GDP growth projected at only around 1½ percent for the foreseeable future,\n    further labor and product market reforms are needed to increase productivity growth, raise\n    potential output, and integrate vulnerable groups into the labor market.\n\n\uf0b7   Third, although the financial sector has recovered since the crisis and is generally sound, cyclical\n    vulnerabilities are rising and new challenges are emerging, suggesting the need for vigilance\n    and proactive policies.3\n\n8.      The government agreed last summer on a new package of measures related to\ntaxation, the labor market, and social benefits (Table 2 and Box 1). The most notable reform was\na reduction in Belgium's corporate income tax (CIT) rate from 34 percent to 25 percent, to be\nphased in over the next three years (SMEs will benefit from a reduced rate of 20 percent starting in\n2018). To compensate for the resulting revenue loss, the notional interest rate deduction (NID) was\nmodified to apply only to incremental corporate equity rather than to the total stock, and new anti-\ntax avoidance measures were introduced consistent with Belgium's EU obligations.4 Together, the\nmeasures are designed to enhance Belgium's competitiveness while preserving revenue neutrality.\n\n9.      Policy discussions focused on the importance of maintaining the reform momentum\nand not yielding to complacency. Achieving the balanced budget goal will require efforts at all\nlevels of government to make spending more efficient and safeguard revenues (Section A).\nA combination of policies and reforms could help raise productivity growth, including increasing\ninvestment in infrastructure and enhancing competition in services (Section B). To fully realize\nBelgium's employment potential, it will be critical to address the severe fragmentation of the labor\nmarket (Section C). To preserve financial stability, the authorities should address vulnerabilities in the\nmortgage market and carefully navigate the transition toward a European Banking Union (Section D).\n\n\n\n\n3\n A comprehensive assessment of Belgium's financial sector took place in 2017 under the Financial Sector\nAssessment Program (FSAP).\n4\n  The NID aims to neutralize the CIT treatment of debt and equity by supplementing the deductibility of interest with\na deduction that is the product of corporate equity and a notional interest rate.\n\n\n8"
for r in re.findall(r'(?sm)^\d\d?\. {3,7}(.*?)(?=\n\n\d\d?\. |\Z)', s):
    print(r, "\n---------")

输出:

The current recovery is an opportunity to strengthen the resilience and growth
potential of the Belgian economy. The government's ability to deal with future shocks will depend
on whether it implements the right policies now while the economy continues to recover.

   First, with public debt above 100 percent of GDP and only starting to come down, Belgium still
    has a long way to go to rebuild buffers and achieve a more sustainable fiscal position. This will
    require following through on plans to gradually move toward structural balance.

   Second, with real GDP growth projected at only around 1½ percent for the foreseeable future,
    further labor and product market reforms are needed to increase productivity growth, raise
    potential output, and integrate vulnerable groups into the labor market.

   Third, although the financial sector has recovered since the crisis and is generally sound, cyclical
    vulnerabilities are rising and new challenges are emerging, suggesting the need for vigilance
    and proactive policies.3 
---------
The government agreed last summer on a new package of measures related to
taxation, the labor market, and social benefits (Table 2 and Box 1). The most notable reform was
a reduction in Belgium's corporate income tax (CIT) rate from 34 percent to 25 percent, to be
phased in over the next three years (SMEs will benefit from a reduced rate of 20 percent starting in
2018). To compensate for the resulting revenue loss, the notional interest rate deduction (NID) was
modified to apply only to incremental corporate equity rather than to the total stock, and new anti-
tax avoidance measures were introduced consistent with Belgium's EU obligations.4 Together, the
measures are designed to enhance Belgium's competitiveness while preserving revenue neutrality. 
---------
Policy discussions focused on the importance of maintaining the reform momentum
and not yielding to complacency. Achieving the balanced budget goal will require efforts at all
levels of government to make spending more efficient and safeguard revenues (Section A).
A combination of policies and reforms could help raise productivity growth, including increasing
investment in infrastructure and enhancing competition in services (Section B). To fully realize
Belgium's employment potential, it will be critical to address the severe fragmentation of the labor
market (Section C). To preserve financial stability, the authorities should address vulnerabilities in the
mortgage market and carefully navigate the transition toward a European Banking Union (Section D).




3
 A comprehensive assessment of Belgium's financial sector took place in 2017 under the Financial Sector
Assessment Program (FSAP).
4
  The NID aims to neutralize the CIT treatment of debt and equity by supplementing the deductibility of interest with
a deduction that is the product of corporate equity and a notional interest rate.


8 
---------