Question

我有一个包含以下数据的xml文件

<year>2013</year>
<youSaveSpend>2500</youSaveSpend>
<yourMpgVehicle>
<avgMpg>32.261695541</avgMpg>
<cityPercent>43</cityPercent>
<highwayPercent>57</highwayPercent>
</yourMpgVehicle>

<year>2013</year>
<youSaveSpend>3000</youSaveSpend>
<yourMpgVehicle>
<avgMpg>33.383275416</avgMpg>
<cityPercent>49</cityPercent>
<highwayPercent>51</highwayPercent>
</yourMpgVehicle>

<year>2012</year>
<youSaveSpend>2500</youSaveSpend>
<yourMpgVehicle>
<avgMpg>36.210640188</avgMpg>
<cityPercent>32</cityPercent>
<highwayPercent>68</highwayPercent>
</yourMpgVehicle>

我想使用BeautifulSoup返回仅2013年的avgMpg列表？我怎么能这样做？

我目前的努力是：

for item in soupedCarAvgMpgPage.findAll('year'):
    listOfYears.append(''.join(item.findAll(text=True)))

for item in soupedCarAvgMpgPage.findAll('avgmpg'):
    listOfAvgMpg.append(''.join(item.findAll(text=True)))

print listOfYears
print listOfAvgMpg;

dictionaryYearToAvgMpg = dict(zip(listOfYears, listOfAvgMpg));

但字典不接受重复：S

Answer 1

由于我们知道元素彼此靠近，我们可以通过搜索next_siblings来实现：

from bs4 import BeautifulSoup

with open('mpg.xml') as f:
    contents=f.read()

mpgs = BeautifulSoup(contents)

def find_nearest_vehicle(elem):
    for sibling in elem.next_siblings:
        if sibling.name == 'yourmpgvehicle':
            return sibling

def find_avg_mpg(elem):
    for child in elem.children:
        if child.name == 'avgmpg':
            return child

year_2013 = [year for year in mpgs.find_all('year')
             if year.string == '2013']

avgmpg = [find_avg_mpg(find_nearest_vehicle(elem)).string
          for elem in year_2013]

print(avgmpg)

当我在你的档案上运行时，我得到：

$ python3 mpg.py
['32.261695541', '33.383275416']

Answer 2

你几乎就在那里，你可以改变你的最后一行：

result = [avgMpg for year, avgMpg in zip(listOfYears, listOfAvgMpg) if year=='2013']

请注意，2013是一个字符串，而不是整数。

或者，对于缩短的整体代码（我将年份转换为int s和avgMpg转换为float s）：

from bs4 import BeautifulSoup as BS
soup = BS(string, 'lxml')
listOfYears = [int(el.string) for el in soup.find_all('year')]
listOfAvgMpg = [float(el.string) for el in soup.find_all('avgmpg')]
result = [avgMpg for year, avgMpg in zip(listOfYears, listOfAvgMpg) if year==2013]
print result

结果：

[32.261695541, 33.383275416]

BeautifulSoup：如何获取最近的标签

2 个答案: