python3在txt文件中的两个字符串之间提取字符串

Question

我是 Python 新手。我正在尝试从一个 txt 文件（“infile.txt”）中提取一个字符串（“我们的披露控制自始至终有效”）。该文件比较大，我需要在一个特定部分（“ITEM & nbsp;9A”和“ITEM & nbsp;9B”之间）查找上述字符串。此类部分的示例如下：

</A>ITEM&nbsp;9A. CONTROLS AND PROCEDURES. </B></FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Evaluation of Disclosure Controls and Procedures </B></FONT> STYLE="margin-top:6px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">Under the supervision and with the participation of our management, including our Chief Executive Officer and Chief Financial Officer, we conducted an evaluation of the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (Exchange Act)), as of the end of the period covered by this Annual Report on Form 10-K. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on such evaluation, our Chief Executive Officer and Chief Financial Officer concluded that our disclosure controls and procedures were effective as of September&nbsp;28, 2012. </FONT></P> <P STYLE="margin-top:18px;margin-bottom:0px"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Management&#146;s Annual Report on Internal Control over Financial Reporting </B></FONT> <P STYLE="margin-top:6px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">This Annual Report does not include a report of management&#146;s assessment regarding internal control over financial reporting or an attestation report of the company&#146;s registered public accounting firm due to a transition period established by rules of the Securities and Exchange Commission for newly public companies. </FONT> <P STYLE="margin-top:18px;margin-bottom:0px"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Changes in Internal Control over Financial Reporting </B></FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">There were no changes in our internal control over financial reporting (as defined in Rule&nbsp;13a-15(f) under the Exchange Act) during the quarter ended September&nbsp;28, 2012, that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting. </FONT> <P STYLE="margin-top:18px;margin-bottom:0px"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B><A NAME="tx431171_16"></A>ITEM&nbsp;9B. OTHER INFORMATION.

如果该部分具有所需的字符串“断定我们的披露控制自生效之日起”（上述部分大约在中间），那么我想在单独的“输出”中打印一个“1”。 csv”文件，如果没有，打印“未找到”。部分的起点并不总是与线的起点重合。很抱歉，但不知道如何开始......我使用的是 Python 3.6。

非常感谢您！

Answer 1

你可以使用re.findall:

import re

the_data = re.findall("</A>ITEM&nbsp;9A. (.*?)</B>", string_data_from_file)

if len(the_data) >0:
    print "1"

else:
    print "Not found"

Answer 2

您可以使用regular expressions 来提取给定开瓶器和关卡器之间的文本：

import re

opener = re.escape(r"ITEM 9A")
closer = re.escape(r"ITEM 9B")

您可以使用 re.finditer 查看提取，然后使用 in-operator 过滤带有目标字符串的提取：

target_string = "concluded that our disclosure controls were effective as of"
for mo in re.finditer(opener + '(.*?)' + closer, inputstring, re.DOTALL):
    extract = mo.group(1)
    if target_string in extract:
        ...

希望这足以让你开始:-)