擅长:python、mysql、java
<p>如果不加入索引,请使用<code>merge</code>:</p>
<pre><code>merged = pd.merge(DataFrameA,DataFrameB, on=['Code','Date'])
</code></pre>
<p><strong>跟进以下问题:</strong></p>
<p>下面是一个可重复的示例:</p>
<pre><code>import pandas as pd
# create some timestamps for date column
i = pd.to_datetime(pd.date_range('20140601',periods=2))
#create two dataframes to merge
df = pd.DataFrame({'code': ['ABC','EFG'], 'date':i,'col1': [10,100]})
df2 = pd.DataFrame({'code': ['ABC','EFG'], 'date':i,'col2': [10,200]})
#merge on columns (default join is inner)
pd.merge(df, df2, on =['code','date'])
</code></pre>
<p>结果是:</p>
<pre><code> code col1 date col2
0 ABC 10 2014-06-01 10
1 EFG 100 2014-06-02 200
</code></pre>
<p>运行此代码时会发生什么情况?</p>