如何在 Python 中使用正则表达式从重定向 URL 中提取 URL？

Question

我有以下test_string ，我需要从中获取实际的 URL。

测试字符串（部分显示）：

An experimental and modeling study of autoignition characteristics of
butanol/diesel blends over wide temperature ranges
<http://scholar.google.com/scholar_url?url=3Dhttps://www.sciencedirect.com/=
science/article/pii/S0010218020301346&hl=3Den&sa=3DX&d=3D448628313728630325=
1&scisig=3DAAGBfm26Wh2koXdeGZkQxzZbenQYFPytLQ&nossl=3D1&oi=3Dscholaralrt&hi=
st=3Dv2Y_3P0AAAAJ:17949955323429043383:AAGBfm1nUe-t2q_4mKFiHSHFEAo0A4rRSA>
Y Qiu, W Zhou, Y Feng, S Wang, L Yu, Z Wu, Y Mao=E2=80=A6 - Combustion and =
Flame,
2020

部分 test_string 所需的 output

https://www.sciencedirect.com/science/article/pii/S0010218020301346

我一直在尝试将下面给出的 MWE 应用于许多字符串，但它只给出了一个 URL。

MWE

from urlparse import urlparse, parse_qs
import re
from re import search

test_string = '''
Production, Properties, and Applications of ALPHA-Terpineol
<http://scholar.google.com/scholar_url?url=https://link.springer.com/content/pdf/10.1007/s11947-020-02461-6.pdf&hl=en&sa=X&d=12771069332921982368&scisig=AAGBfm1tFjLUm7GV1DRnuYCzvR4uGWq9Cg&nossl=1&oi=scholaralrt&hist=v2Y_3P0AAAAJ:17949955323429043383:AAGBfm1nUe-t2q_4mKFiHSHFEAo0A4rRSA>

A Sales, L de Oliveira Felipe, JL Bicas
Abstract ALPHA-Terpineol (CAS No. 98-55-5) is a tertiary monoterpenoid 
alcohol widely
and commonly used in the flavors and fragrances industry for its sensory 
properties.
It is present in different natural sources, but its production is mostly 
based on ...
Save 
<http://scholar.google.com/citations?update_op=email_library_add&info=oB2z7uTzO7EJ&citsig=AMD79ooAAAAAYLfmix3sQyUWnFrHeKYZxuK31qlqlbCh&hl=en> 
    Twitter 
<http://scholar.google.com/scholar_share?hl=en&oi=scholaralrt&ss=tw&url=https://link.springer.com/content/pdf/10.1007/s11947-020-02461-6.pdf&rt=Production,+Properties,+and+Applications+of+%CE%B1-Terpineol&scisig=AAGBfm0yXFStqItd97MUyPT5nRKLjPIK6g> 
    Facebook 
<http://scholar.google.com/scholar_share?hl=en&oi=scholaralrt&ss=fb&url=https://link.springer.com/content/pdf/10.1007/s11947-020-02461-6.pdf&rt=Production,+Properties,+and+Applications+of+%CE%B1-Terpineol&scisig=AAGBfm0yXFStqItd97MUyPT5nRKLjPIK6g> 

An experimental and modeling study of autoignition characteristics of
butanol/diesel blends over wide temperature ranges
<http://scholar.google.com/scholar_url?url=3Dhttps://www.sciencedirect.com/=
science/article/pii/S0010218020301346&hl=3Den&sa=3DX&d=3D448628313728630325=
1&scisig=3DAAGBfm26Wh2koXdeGZkQxzZbenQYFPytLQ&nossl=3D1&oi=3Dscholaralrt&hi=
st=3Dv2Y_3P0AAAAJ:17949955323429043383:AAGBfm1nUe-t2q_4mKFiHSHFEAo0A4rRSA>
Y Qiu, W Zhou, Y Feng, S Wang, L Yu, Z Wu, Y Mao=E2=80=A6 - Combustion and =
Flame,
2020
Butanol/diesel blend is considered as a very promising alternative fuel
with
agreeable combustion and emission performance in engines. This paper
intends to
further investigate its autoignition characteristics with the combination
of a heated =E2=80=A6
[image: Save]
<http://scholar.google.com/citations?update_op=3Demail_library_add&info=3DE=
27Gd756Qj4J&citsig=3DAMD79ooAAAAAYImDxwWCwd5S5xIogWp9RTavFRMtTDgS&hl=3Den>
[image:
Twitter]
<http://scholar.google.com/scholar_share?hl=3Den&oi=3Dscholaralrt&ss=3Dtw&u=
rl=3Dhttps://www.sciencedirect.com/science/article/pii/S0010218020301346&rt=
=3DAn+experimental+and+modeling+study+of+autoignition+characteristics+of+bu=
tanol/diesel+blends+over+wide+temperature+ranges&scisig=3DAAGBfm19DOLNm3-Fl=
WaO0trAxZkeidxYWg>
[image:
Facebook]
<http://scholar.google.com/scholar_share?hl=3Den&oi=3Dscholaralrt&ss=3Dfb&u=
rl=3Dhttps://www.sciencedirect.com/science/article/pii/S0010218020301346&rt=
=3DAn+experimental+and+modeling+study+of+autoignition+characteristics+of+bu=
tanol/diesel+blends+over+wide+temperature+ranges&scisig=3DAAGBfm19DOLNm3-Fl=
WaO0trAxZkeidxYWg>

Using NMR spectroscopy to investigate the role played by copper in prion
diseases.
<http://scholar.google.com/scholar_url?url=3Dhttps://europepmc.org/article/=
med/32328835&hl=3Den&sa=3DX&d=3D16122276072657817806&scisig=3DAAGBfm1AE6Kyl=
jWO1k0f7oBnKFClEzhTMg&nossl=3D1&oi=3Dscholaralrt&hist=3Dv2Y_3P0AAAAJ:179499=
55323429043383:AAGBfm1nUe-t2q_4mKFiHSHFEAo0A4rRSA>
RA Alsiary, M Alghrably, A Saoudi, S Al-Ghamdi=E2=80=A6 - =E2=80=A6 and of =
the Italian
Society of =E2=80=A6, 2020
Prion diseases are a group of rare neurodegenerative disorders that develop
as a
result of the conformational conversion of normal prion protein (PrPC) to
the disease-
associated isoform (PrPSc). The mechanism that actually causes disease
remains =E2=80=A6
[image: Save]
<http://scholar.google.com/citations?update_op=3Demail_library_add&info=3Dz=
pCMKavUvd8J&citsig=3DAMD79ooAAAAAYImDx3r4gltEWBAkhl0g2POsXB9Qn4Lk&hl=3Den>
[image:
Twitter]
<http://scholar.google.com/scholar_share?hl=3Den&oi=3Dscholaralrt&ss=3Dtw&u=
rl=3Dhttps://europepmc.org/article/med/32328835&rt=3DUsing+NMR+spectroscopy=
+to+investigate+the+role+played+by+copper+in+prion+diseases.&scisig=3DAAGBf=
m1RidyRD-x2FOemP6iqCsr-6GAVKA>
[image:
Facebook]
<http://scholar.google.com/scholar_share?hl=3Den&oi=3Dscholaralrt&ss=3Dfb&u=
rl=3Dhttps://europepmc.org/article/med/32328835&rt=3DUsing+NMR+spectroscopy=
+to+investigate+the+role+played+by+copper+in+prion+diseases.&scisig=3DAAGBf=
m1RidyRD-x2FOemP6iqCsr-6GAVKA>


'''

regex = re.compile('(http://scholar.*?)&')
url_all = regex.findall(test_string)
citation_url = []
for i in url_all:
    if search('scholar.google.com',i):
        qs = parse_qs(urlparse(i).query).values()
        if search('http',str(qs[0])):
            citation_url.append(qs[0])
print citation_url

目前output

https://link.springer.com/content/pdf/10.1007/s11947-020-02461-6.pdf

所需 output

https://link.springer.com/content/pdf/10.1007/s11947-020-02461-6.pdf
https://www.sciencedirect.com/science/article/pii/S0010218020301346
https://europepmc.org/article/med/3232883

如何处理 URL 文本换行与等号并在 Python 中提取重定向 URL？

Answer 1

您可以使用字符 class 匹配问号或与号[&?] 。 查看示例数据，对于url=部分，您可以添加可选的换行符和可选的等号并进行相应调整。

一些 url 以 3D 开头，您可以使用非捕获组(?:3D)?

然后在匹配 http 的第 1 组中捕获，然后匹配除&之外的所有字符

\bhttp://scholar\.google\.com.*?[&?]\n?u=?\n?r\n?l\n?=(?:3D)?(http[^&]+)

正则表达式演示

Answer 2

看到这个正则表达式模式，我认为它可能有助于提取重定向 uri

(http:\/\/scholar[\w.\/=&?]*)[?]?u[=]?rl=([\w\:.\/\-=]+)

也可以在这里看到这个例子https://regex101.com/r/dmkF3h/3