<p>您可以使用<a href="https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.Series.map.html" rel="nofollow noreferrer">^{<cd1>}</a>:</p>
<pre><code>import collections
import pandas as pd
c = collections.Counter({u'Apple': 1638, u'Facebook': 1169, u'Amazon': 1027, u'Boeing': 548, u'Microsoft': 437, u'JPMorgan': 435, u'Nasdaq': 364, u'Williams': 296, u'Disney': 270, u'Netflix': 260, u'Chevron': 258, u'Comcast': 213, u'CBS': 200, u'Carnival': 193, u'Intel': 188,
u'IBM': 172, u'Starbucks': 165, u'Target': 143, u'Monsanto': 141, u'PayPal': 133, u'Viacom': 126, u'Equifax': 124, u'Anthem': 123, u'Pfizer': 121, u'Nike': 121, u'Caterpillar': 119, u'Citigroup': 116, u'AIG': 116, u'HP': 109, u'Aetna': 109, u'BlackRock': 109})
df = pd.DataFrame({'Name': {0: '3M',
1: 'A.O. Smith',
2: 'Abbott',
3: 'AbbVie',
4: 'Accenture',
5: 'Activision',
6: 'Acuity Brands',
7: 'AIG'},
'Frequency': {0: 0, 1: 0, 2: 0, 3: 0, 4: 0, 5: 0, 6: 0, 7: 10}})
df['Frequency'] = df['Name'].map(c)
print(df)
</code></pre>
<p>收益率</p>
^{pr2}$
<p>我向<code>df</code>添加了一行以显示一个非常重要的结果。在</p>
<p>当<code>c</code>中没有对应的键时,<code>Series.map(c)</code>会使序列保持独立。因此,只有在<code>c</code>中具有对应键的行才会被更新。在</p>