Python中的字符串函数以在两个字符之间提取

Question

我有以下字符串，我想提取一切从<img...到收盘"后.jpg 。

我尝试了以下操作，但它不仅找到第一个" ，而且还找到了最后一个。

有人可以帮忙吗？

In [14]: start = 'img src="'
In [15]: end = '"'
print string[string.find(start)+len(start):string.rfind(end)]

串：

 <p><a href="https://news.yahoo.com/us-ambassador-takes-post-united-nations-141833297.html"><img src="http://l1.yimg.com/uu/api/res/1.2/1f8jyGM.NfkxLb_.OgMaIQ--/YXBwaWQ9eXRhY2h5b247aD04Njt3PTEzMDs-/http://media.zenfs.com/en_us/News/afp.com/f5bbc19135065fcfff40e6ece9650f4ab225fa97.jpg" width="130" height="86" alt="New US ambassador takes up post at United Nations" align="left" title="New US ambassador takes up post at United Nations" border="0" ></a>US Ambassador Kelly Craft took up her post at the United Nations on Thursday, vowing to defend America's values and interests nine months after the departure of her high-profile predecessor Nikki Haley. Craft, 57, served previously as US ambassador to Canada where she was involved in negotiations on a new US Mexico Canada free trade agreement.<p><br clear="all">

Answer 1

如果您确定它总是一样的话，可以使用Regex这样。

<img.*?jpg\\"

这是它的链接， Regex101您可以根据需要进行调整。 正则表达式是正确的工具，而不是麻烦find和len等等。

Answer 2

如果您不想使用正则表达式，则可以只使用.split（）函数。

str = """<p><a href="https://news.yahoo.com/us-ambassador-takes-post-united-nations-141833297.html"><img src="http://l1.yimg.com/uu/api/res/1.2/1f8jyGM.NfkxLb_.OgMaIQ--/YXBwaWQ9eXRhY2h5b247aD04Njt3PTEzMDs-/http://media.zenfs.com/en_us/News/afp.com/f5bbc19135065fcfff40e6ece9650f4ab225fa97.jpg" width="130" height="86" alt="New US ambassador takes up post at United Nations" align="left" title="New US ambassador takes up post at United Nations" border="0" ></a>US Ambassador Kelly Craft took up her post at the United Nations on Thursday, vowing to defend America's values and interests nine months after the departure of her high-profile predecessor Nikki Haley. Craft, 57, served previously as US ambassador to Canada where she was involved in negotiations on a new US Mexico Canada free trade agreement.<p><br clear="all">"""


#final should just be the url
final = str.split("img src=\"")[1].split("\" width=")[0]

print(final)

输出：

http://l1.yimg.com/uu/api/res/1.2/1f8jyGM.NfkxLb_.OgMaIQ--/YXBwaWQ9eXRhY2h5b247aD04Njt3PTEzMDs-/http://media.zenfs.com/en_us/News/afp.com/f5bbc19135065fcfff40e6ece9650f4ab225fa97.jpg