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<p>我有一只熊猫<code>DataFrame</code>如下。</p>
<pre><code>df = pd.DataFrame({'id' : [1,1,1,2,2,3,3,3,3,4,4,5,6,6,6,7,7],
'value' : ["first","second","second","first",
"second","first","third","fourth",
"fifth","second","fifth","first",
"first","second","third","fourth","fifth"]})
</code></pre>
<p>我想按[“id”,“value”]对它进行分组,并得到每个组的第一行。</p>
<pre><code> id value
0 1 first
1 1 second
2 1 second
3 2 first
4 2 second
5 3 first
6 3 third
7 3 fourth
8 3 fifth
9 4 second
10 4 fifth
11 5 first
12 6 first
13 6 second
14 6 third
15 7 fourth
16 7 fifth
</code></pre>
<p>预期成果</p>
<pre><code> id value
1 first
2 first
3 first
4 second
5 first
6 first
7 fourth
</code></pre>
<p>我试着跟随它,它只给出<code>DataFrame</code>的第一行。如有任何帮助,我们将不胜感激。</p>
<pre><code>In [25]: for index, row in df.iterrows():
....: df2 = pd.DataFrame(df.groupby(['id','value']).reset_index().ix[0])
</code></pre>