如何在Pandas中读取带有行名称的数据框的CSV文件

Question

I have a CSV file ( tmp.csv ) that looks like this:

        x       y       z
bar     0.55    0.55    0.0
foo     0.3     0.4     0.1
qux     0.0     0.3     5.55

It was created with Pandas this way:

    In [103]: df_dummy 
    Out[103]: 
          x     y     z
    bar  0.55  0.55  0.00
    foo  0.30  0.40  0.10
    qux  0.00  0.30  5.55

   In [104]: df_dummy.to_csv("tmp.csv",sep="\t")   

What I want to do is to read that CSV into the same dataframe representation. I tried this but doesn't give what I want:

In [108]: pd.io.parsers.read_csv("tmp.csv",sep="\t")
Out[108]: 
  Unnamed: 0     x     y     z
0        bar  0.55  0.55  0.00
1        foo  0.30  0.40  0.10
2        qux  0.00  0.30  5.55

What's the right way to do it?

Answer 1

You can use index_col parameter:

>>> pd.io.parsers.read_csv("tmp.csv",sep="\t",index_col=0)
        x     y     z
bar  0.55  0.55  0.00
foo  0.30  0.40  0.10
qux  0.00  0.30  5.55