Question

以下网址：

http://www.cbs.gov.il/ts/ID40d250e0710c2f/databank/series_func_e_v1.html?level_1=31&level_2=1&level_3=7

向以色列政府提供信息数据生成器，将一次提取的数据点数限制为最多50个系列。我想知道，是否有可能（如果是这样，如何）编写一个webscraper（用你喜欢的语言/软件），它可以跟随每一步的点击，以便能够获得特定主题中的所有系列。

感谢。

Answer 1

查看WWW::Mechanize和WWW::HtmlUnit。

#!/usr/bin/perl

use strict;
use warnings;

use WWW::Mechanize;

my $m = WWW::Mechanize->new;

#get page
$m->get("http://www.cbs.gov.il/ts/ID40d250e0710c2f/databank/series_func_e_v1.html?level_1=31&level_2=1&level_3=7");

#submit the form on the first page
$m->submit_form(
    with_fields => {
        name_tatser => 2, #Orders for export
    }
);

#now that we have the second page, submit the form on it
$m->submit_form(
    with_fields => {
        name_ser => 1576, #Number of companies that answered
    }
);

#and so on...

#printing the source HTML is a good way
#to find out what you need to do next
print $m->content;

Answer 2

要提交表单，您可以使用Python's mechanize module：

import mechanize
import pprint
import lxml.etree as ET
import lxml.html as lh
import urllib
import urllib2

browser=mechanize.Browser()
browser.open("http://www.cbs.gov.il/ts/ID40d250e0710c2f/databank/series_func_e_v1.html?level_1=31&level_2=1&level_3=7")
browser.select_form(nr=0)

我们在这里查看可用选项：

pprint.pprint(browser.form.controls[-2].items)
# [<Item name='1' id=None selected='selected' contents='Volume of orders for the domestic market' value='1' label='Volume of orders for the domestic market'>,
#  <Item name='2' id=None contents='Orders for export' value='2' label='Orders for export'>,
#  <Item name='3' id=None contents='The volume of production' value='3' label='The volume of production'>,
#  <Item name='4' id=None contents='The volume of sales' value='4' label='The volume of sales'>,
#  <Item name='5' id=None contents='Stocks of finished goods' value='5' label='Stocks of finished goods'>,
#  <Item name='6' id=None contents='Access to credit for the company' value='6' label='Access to credit for the company'>,
#  <Item name='7' id=None contents='Change in the number of employees' value='7' label='Change in the number of employees'>]

choices=[item.attrs['value'] for item in browser.form.controls[-2].items]
print(choices)
# ['1', '2', '3', '4', '5', '6', '7']

browser.form['name_tatser']=['2']
browser.submit()

我们可以为每个后续表格重复这个：

browser.select_form(nr=1)

choices=[item.attrs['value'] for item in browser.form.controls[-2].items]
print(choices)
# ['1576', '1581', '1594', '1595', '1596', '1598', '1597', '1593']

browser.form['name_ser']=['1576']
browser.submit()

browser.select_form(nr=2)

choices=[item.attrs['value'] for item in browser.form.controls[-2].items]
print(choices)
# ['32', '33', '34', '35', '36', '37', '38', '39', '40', '41']

browser.form['data_kind']=['33']
browser.submit()

browser.select_form(nr=3)
browser.form['ybegin']=['2010']
browser.form['mbegin']=['1']
browser.form['yend']=['2011']
browser.form['mend']=['5']
browser.submit()

此时您有三个选择：

解析HTML源代码中的数据
下载.xls文件
下载XML文件

我没有在Python中解析.xls的经验，所以我通过了这个选项。

使用BeautifulSoup或lxml解析HTML。也许这本来是最短的解决方案，但找不到HTML的正确XPath对我来说并不是很清楚，所以我选择了XML：

要从cbs.gov.il网站下载XML，只需点击一个调用javascript函数的按钮即可。哦哦 - 机械化无法执行javascript函数。值得庆幸的是，javascript只是组装了一个新的url。使用lxml拉出参数很简单：

content=browser.response().read()
doc=lh.fromstring(content)
params=dict((elt.attrib['name'],elt.attrib['value']) for elt in doc.xpath('//input'))
params['king_format']=2
url='http://www.cbs.gov.il/ts/databank/data_ts_format_e.xml'
params=urllib.urlencode(dict((p,params[p]) for p in [
    'king_format',
    'tod',
    'time_unit_list',
    'mend',
    'yend',
    'co_code_list',
    'name_tatser_list',
    'ybegin',
    'mbegin',
    'code_list',
    'co_name_tatser_list',
    'level_1',
    'level_2',
    'level_3']))

browser.open(url+'?'+params)
content=browser.response().read()

现在我们到达另一个绊脚石：XML在iso-8859-8-i中编码。 Python无法识别此编码。我不知道该怎么做，只是将iso-8859-8-i替换为iso-8859-8。我不知道这会造成什么不良副作用。

# A hack, since I do not know how to deal with iso-8859-8-i
content=content.replace('iso-8859-8-i','iso-8859-8')
doc=ET.fromstring(content)

一旦你做到这一点，解析XML很容易：

for series in doc.xpath('/series_ts/Data_Set/Series'):
    print(series.attrib)
    # {'calc_kind': 'Weighted',
    #  'name_ser': 'Number Of Companies That Answered',
    #  'get_time': '2011-06-21',
    #  'name_topic': "Business Tendency Survey - Distributions Of Businesses By Industry, Kind Of Questions And Answers  - Manufacturing - Company'S Experience Over The Past Three Months - Orders For Export",
    #  'time_unit': 'Month',
    #  'code_series': '22978',
    #  'data_kind': '5-10 Employed Persons',
    #  'decimals': '0',
    #  'unit_kind': 'Number'}

    for elt in series.xpath('obs'):
        print(elt.attrib)
        # {'time_period': ' 2010-12', 'value': '40'}
        # {'time_period': ' 2011-01', 'value': '38'}
        # {'time_period': ' 2011-02', 'value': '40'}
        # {'time_period': ' 2011-03', 'value': '36'}
        # {'time_period': ' 2011-04', 'value': '30'}
        # {'time_period': ' 2011-05', 'value': '33'}

Answer 3

您还应该查看Scrapy，它是Python的Web爬网程序框架。有关简介，请参阅'Scrapy一览'：http://doc.scrapy.org/intro/overview.html

我如何从以色列统计局的网络查询工具中获取数据？

3 个答案: