Tre*_*vor 3 python regex python-2.7
我试图让我的头围绕一些正则表达式(使用Python 2.7)并且遇到了令人困惑的障碍.这与(.*)有关.我知道除了你使用标签re.DOTALL之外,dot除了新行之外还匹配所有内容.但是当我使用标签时,它包含太多.以下是我尝试过的一些变体和结果的代码:
import re
from urllib2 import urlopen
webpage = urlopen('http://trev.id.au/testfiles/rgxtxt.php').read()
# find the instances of pattern in the file
findPatHTMLComment = re.findall('<!--(.*)-->',webpage)
foundItems = len(findPatHTMLComment) # how many instances where found?
# Print results
print "Found " + str(foundItems) + " matches. They are: "
listIterator = []
listIterator[:]=range(0,foundItems)
for i in listIterator:
print "HTML_Comment["+ str(i) +"]: |" + findPatHTMLComment[i] + "| END HTML Comment"
这导致找到3个匹配,因为它没有找到多行注释部分.
使用:
findPatHTMLComment = re.findall('<!--(.*)-->',webpage,re.DOTALL)
使用文档末尾的第一个匹配查找单个匹配项.
findPatHTMLComment = re.findall('<!--(.*)-->',webpage,re.MULTILINE)
查找与第一个相同的内容,文件中的5个注释中只有3个.
问题:在这个例子中我应该使用什么作为正则表达式？你能为我和其他人解释一下吗？
感谢您提供的任何指导.感谢,并有一个愉快的一天.
编辑:包括上面代码中链接的样本数据(将很快从服务器中删除样本数据):
<html>
<!--[if lt IE 9 ]>
<script type="text/javascript">
jQuery(function ($) {
function TopSearchIE9(input,inputBtn){
var $topSearch=$(input);
var $topSearchBtn=$(inputBtn);
$topSearch.keydown(function(e) {
if (e.keyCode == 13) {
$topSearchBtn.trigger("click");
return false;
}
});
}
TopSearchIE9(".J-txt-focus1",".J-txt-focus1-btn");
TopSearchIE9(".J-txt-focus2",".J-txt-focus2-btn");
});
</script>
<![endif]-->
<!--[if lt IE 10 ]>
<style>
.new-header-search .hdSch-txt{ width: 225px;}
.new-header-search .hdSch-del{width: 0px; padding: 5px 0px;}
.new-header-search .hdSch-del.del{background:none; padding: }
</style>
<![endif]-->
<body>
<!-- This is a text file with a number of items to allow testing of some regex methods. It has no actual meaning -->
<div head1>Item heading for first item</div>
<!--By the way, this is a comment in a block of HTML text.-->
<div itembody>We can jump over the moon if we are fast enough, but we really shouldn't try it cause we may get a blood nose. When we do try and succeed it feels quite good.</div>
<div head1>Item heading for second item</div>
<div itembody>If this is showing, its the second body within the itembody div tags for this file</div>
<div head1>Item heading for the third item</div>
<div itembody>
Going to add another div tag
<div highlight>
and closing div tag
</div>
in this body to see how it handles that.
</div>
<!-- The above itembody data should
have it's own div and closing div tags -->
<div head1>Item heading for the fourth item</div>
<div itembody>
<p><a href="mailto:fred@flinstone.com">email fred</a> or phone him on +63 493 3382 3329 when you are ready to try more regex stuff.</p>
<p>You can also check with Barney by <a href="mailto:barney@rubble.com">emailing him</a> or phone him of +44 394 394 3992 if that is easier</p>
</div>
<!-- Thats all folks... -->
</body>
但是当我使用标签时,它包含太多.
*是一个贪婪的运算符意味着它将尽可能多地匹配并仍然允许正则表达式的其余部分匹配.您需要跟随*操作员?进行非贪婪的匹配,这意味着"零或更多 - 最好尽可能少".
re.findall('<!--(.*?)-->', webpage, re.DOTALL)
?
该re.MULTILINE标志被称为多线,因为锚^和$实施时在多行操作,在这种情况下,使用多线改性剂是多余的.
另外,我会考虑使用BeautifulSoup来完成这项任务.
from bs4 import BeautifulSoup, Comment
soup = BeautifulSoup(html)
comments = soup.find_all(text=lambda text:isinstance(text, Comment))
| 归档时间： |
|
| 查看次数： |
124 次 |
| 最近记录： |