如何使用python从字符串中提取url？

Question

例如:

string = "This is a link http://www.google.com"

我怎样才能提取"http://www.google.com"？

(每个链接的格式相同,即'http://')

Answer 1

可能有几种方法可以做到这一点,但最干净的是使用正则表达式

>>> myString = "This is a link http://www.google.com"
>>> print re.search("(?P<url>https?://[^\s]+)", myString).group("url")
http://www.google.com

如果可以有多个链接,您可以使用类似于下面的内容

>>> myString = "These are the links http://www.google.com  and http://stackoverflow.com/questions/839994/extracting-a-url-in-python"
>>> print re.findall(r'(https?://[^\s]+)', myString)
['http://www.google.com', 'http://stackoverflow.com/questions/839994/extracting-a-url-in-python']
>>> 

Answer 2

要在通用字符串中查找Web URL,可以使用正则表达式(regex).

像下面这样的URL匹配的简单正则表达式应该适合您的情况.

    regex = r'('

    # Scheme (HTTP, HTTPS, FTP and SFTP):
    regex += r'(?:(https?|s?ftp):\/\/)?'

    # www:
    regex += r'(?:www\.)?'

    regex += r'('

    # Host and domain (including ccSLD):
    regex += r'(?:(?:[A-Z0-9][A-Z0-9-]{0,61}[A-Z0-9]\.)+)'

    # TLD:
    regex += r'([A-Z]{2,6})'

    # IP Address:
    regex += r'|(?:\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})'

    regex += r')'

    # Port:
    regex += r'(?::(\d{1,5}))?'

    # Query path:
    regex += r'(?:(\/\S+)*)'

    regex += r')'

如果您想更加精确,在TLD部分,您应该确保TLD是有效的TLD(请参阅此处的完整有效TLD列表:https://data.iana.org/TLD/tlds-alpha- by-domain.txt):

    # TLD:
    regex += r'(com|net|org|eu|...)'

然后,您可以简单地编译前一个正则表达式并使用它来查找可能的匹配项:

    import re

    string = "This is a link http://www.google.com"

    find_urls_in_string = re.compile(regex, re.IGNORECASE)
    url = find_urls_in_string.search(string)

    if url is not None and url.group(0) is not None:
        print("URL parts: " + str(url.groups()))
        print("URL" + url.group(0).strip())

如果字符串"这是一个链接http://www.google.com "将输出:

    URL parts: ('http://www.google.com', 'http', 'google.com', 'com', None, None)
    URL: http://www.google.com

如果您使用更复杂的URL更改输入,例如"这也是URL https://www.host.domain.com:80/path/page.php?query=value&a2=v2#foo但这不是"输出将是:

    URL parts: ('https://www.host.domain.com:80/path/page.php?query=value&a2=v2#foo', 'https', 'host.domain.com', 'com', '80', '/path/page.php?query=value&a2=v2#foo')
    URL: https://www.host.domain.com:80/path/page.php?query=value&a2=v2#foo

注意:如果您要在单个字符串中查找更多URL,您仍然可以使用相同的正则表达式,但只需使用findall()而不是search().

Answer 3

还有另一种方法可以轻松地从文本中提取URL.您可以使用urlextract为您完成,只需通过pip安装:

pip install urlextract

然后你可以像这样使用它:

from urlextract import URLExtract

extractor = URLExtract()
urls = extractor.find_urls("Let's have URL stackoverflow.com as an example.")
print(urls) # prints: ['stackoverflow.com']

您可以在我的github页面上找到更多信息:https://github.com/lipoja/URLExtract

注意:它会从iana.org下载TLD列表,以使您保持最新状态.但如果该程序没有互联网访问,那么它不适合你.

Answer 4

这会提取所有带有参数的网址，不知何故以上所有示例都对我不起作用

import re

data = 'https://net2333.us3.list-some.com/subscribe/confirm?u=f3cca8a1ffdee924a6a413ae9&id=6c03fa85f8&e=6bbacccc5b'

WEB_URL_REGEX = r"""(?i)\b((?:https?:(?:/{1,3}|[a-z0-9%])|[a-z0-9.\-]+[.](?:com|net|org|edu|gov|mil|aero|asia|biz|cat|coop|info|int|jobs|mobi|museum|name|post|pro|tel|travel|xxx|ac|ad|ae|af|ag|ai|al|am|an|ao|aq|ar|as|at|au|aw|ax|az|ba|bb|bd|be|bf|bg|bh|bi|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|cr|cs|cu|cv|cx|cy|cz|dd|de|dj|dk|dm|do|dz|ec|ee|eg|eh|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|gm|gn|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|ir|is|it|je|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|mv|mw|mx|my|mz|na|nc|ne|nf|ng|ni|nl|no|np|nr|nu|nz|om|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|Ja|sk|sl|sm|sn|so|sr|ss|st|su|sv|sx|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|yu|za|zm|zw)/)(?:[^\s()<>{}\[\]]+|\([^\s()]*?\([^\s()]+\)[^\s()]*?\)|\([^\s]+?\))+(?:\([^\s()]*?\([^\s()]+\)[^\s()]*?\)|\([^\s]+?\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’])|(?:(?<!@)[a-z0-9]+(?:[.\-][a-z0-9]+)*[.](?:com|net|org|edu|gov|mil|aero|asia|biz|cat|coop|info|int|jobs|mobi|museum|name|post|pro|tel|travel|xxx|ac|ad|ae|af|ag|ai|al|am|an|ao|aq|ar|as|at|au|aw|ax|az|ba|bb|bd|be|bf|bg|bh|bi|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|cr|cs|cu|cv|cx|cy|cz|dd|de|dj|dk|dm|do|dz|ec|ee|eg|eh|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|gm|gn|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|ir|is|it|je|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|mv|mw|mx|my|mz|na|nc|ne|nf|ng|ni|nl|no|np|nr|nu|nz|om|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|Ja|sk|sl|sm|sn|so|sr|ss|st|su|sv|sx|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|yu|za|zm|zw)\b/?(?!@)))"""
re.findall(WEB_URL_REGEX, text)