Python: Extracting specific data with html parser

2019-05-14 16:22发布

站内问答 / Python
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I started using the HTMLParser in Python to extract data from a website. I get everything I wanted, except the text within two tags of HTML. Here is an example of the HTML tag:

<a href="http://wold.livingsources.org/vocabulary/1" title="Swahili" class="Vocabulary">Swahili</a>

There are also other tags starting with . They have other attributes and values and therefore I do not want to have their data:

<a href="http://wold.livingsources.org/contributor#schadebergthilo" title="Thilo Schadeberg" class="Contributor">Thilo Schadeberg</a>

The tag is an embedded tag within a table. I don't know if this makes any difference between other tags. I only want the information in some of the tags called 'a' with the attribute class="Vocabulary" and I want the data within the tag, in the example it would be "Swahili". So what I did is:

class AllLanguages(HTMLParser):
    '''
    classdocs
    '''
    #counter for the languages
    #countLanguages = 0
    def __init__(self):
        HTMLParser.__init__(self)
        self.inLink = False
        self.dataArray = []
        self.countLanguages = 0
        self.lasttag = None
        self.lastname = None
        self.lastvalue = None
        #self.text = ""


    def handle_starttag(self, tag, attr):
        #print "Encountered a start tag:", tag      
        if tag == 'a':
            for name, value in attr:
                if name == 'class' and value == 'Vocabulary':
                    self.countLanguages += 1
                    self.inLink = True
                    self.lasttag = tag
                    #self.lastname = name
                    #self.lastvalue = value
                    print self.lasttag
                    #print self.lastname
                    #print self.lastvalue
                    #return tag
                    print self.countLanguages




    def handle_endtag(self, tag):
        if tag == "a":
            self.inlink = False
            #print "".join(self.data)

    def handle_data(self, data):
        if self.lasttag == 'a' and self.inLink and data.strip():
            #self.dataArray.append(data)
            #
            print data

The programm prints every data which is included in an tag, but I only want the one included in the tag with the right attributes. How do I get this specific data?

2条回答
仙女界的扛把子
2楼-- · 2019-05-14 16:56

Looks like you forgot to set self.inLink = False in handle_starttag by default:

from HTMLParser import HTMLParser


class AllLanguages(HTMLParser):
    def __init__(self):
        HTMLParser.__init__(self)
        self.inLink = False
        self.dataArray = []
        self.countLanguages = 0
        self.lasttag = None
        self.lastname = None
        self.lastvalue = None

    def handle_starttag(self, tag, attrs):
        self.inLink = False
        if tag == 'a':
            for name, value in attrs:
                if name == 'class' and value == 'Vocabulary':
                    self.countLanguages += 1
                    self.inLink = True
                    self.lasttag = tag

    def handle_endtag(self, tag):
        if tag == "a":
            self.inlink = False

    def handle_data(self, data):
        if self.lasttag == 'a' and self.inLink and data.strip():
            print data


parser = AllLanguages()
parser.feed("""
<html>
<head><title>Test</title></head>
<body>
<a href="http://wold.livingsources.org/vocabulary/1" title="Swahili" class="Vocabulary">Swahili</a>
<a href="http://wold.livingsources.org/contributor#schadebergthilo" title="Thilo Schadeberg" class="Contributor">Thilo Schadeberg</a>
<a href="http://wold.livingsources.org/vocabulary/2" title="English" class="Vocabulary">English</a>
<a href="http://wold.livingsources.org/vocabulary/2" title="Russian" class="Vocabulary">Russian</a>
</body>
</html>""")

prints:

Swahili
English
Russian

Also, take a look at:

Hope that helps.

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你好瞎i
3楼-- · 2019-05-14 17:00

You may try HTQL (http://htql.net). The query for:

"the tags called 'a' with the attribute class="Vocabulary" and I want the data within the tag"

is:

<a (class='Vocabulary')>:tx

The python code is something like this: 

import htql
a=htql.query(page, "<a (class='Vocabulary')>:tx")
print(a)
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