<p>我从网上网页下载了一个xml格式的数据集。我已经使用python的模式库提取了values标记。这给了我unicode值。</p>
<p>我想把这个unicode数字,比如u'63.3'转换成浮点数。我试过做float(a),但它给出了错误消息。</p>
<pre><code>import numpy as np
import pandas as pd
import requests
from pattern import web
xml = requests.get('http://charts.realclearpolitics.com/charts/1044.xml').text
dom = web.Element(xml)
values = dom.by_tag('value')
date= []
approve = []
disapprove = []
values = dom.by_tag('value')
for i in range(0,1724):
date.<a href="https://www.cnpython.com/list/append" class="inner-link">append</a>(pd.to_datetime(values[i].content))
for i in range(1724,3448):
a = float(values[i].content)
approve.append(a)
for i in range(3448,5172):
a = float(values[i].content)
disapprove.append(a)
finalresult = pd.DataFrame({'date': date, 'Approve': approve, 'Disapprove': disapprove})
finalresult
</code></pre>
<p>输出如下:</p>
<pre><code>---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-12-d9d9e580d883> in <module>()
9
10 for i in range(1724,3448):
---> 11 a = float(values[i].content)
12 result['Approve'].append(a)
13
ValueError: could not convert string to float:
</code></pre>