擅长:python、mysql、java
<p>这些不是对称的,因为在csv格式中由于位置的原因存在歧义。您需要在回读时指定<code>index_col</code></p>
<pre><code>In [1]: x=[('a','a','c') for i in range(5)]
In [2]: df = DataFrame(x,columns=['col1','col2','col3'])
In [3]: df.to_csv('test.csv')
In [4]: !cat test.csv
,col1,col2,col3
0,a,a,c
1,a,a,c
2,a,a,c
3,a,a,c
4,a,a,c
In [5]: pd.read_csv('test.csv',index_col=0)
Out[5]:
col1 col2 col3
0 a a c
1 a a c
2 a a c
3 a a c
4 a a c
</code></pre>
<p>这看起来与上面非常相似,所以“foo”是列还是索引?</p>
<pre><code>In [6]: df.index.name = 'foo'
In [7]: df.to_csv('test.csv')
In [8]: !cat test.csv
foo,col1,col2,col3
0,a,a,c
1,a,a,c
2,a,a,c
3,a,a,c
4,a,a,c
</code></pre>