pandas 如何在pandas df中设置新索引并删除默认索引
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How to set new index and remove default index in pandas df
提问by kshama
I have attached the dataframe in the pic. In the df, subVoyageID is the default index, I am trying to remove that blank row next to the subvoyageID, so that all the column names are aligned in the same row, but I am unable to do it.
我已在图片中附加了数据框。在 df 中，subVoyageID 是默认索引，我试图删除 subvoyageID 旁边的空白行，以便所有列名都在同一行中对齐，但我无法这样做。
Since subVoyageID is the default index, I copied the data into new col "svid" and reset the index to new column "svid", (see the code and pic below)
由于 subVoyageID 是默认索引，我将数据复制到新列“svid”并将索引重置为新列“svid”，（请参阅下面的代码和图片）
df["SVID"] = df.index
df.set_index('SVID')
df
Original df
原始文件
Resultant df
结果 df
Now how do I get rid of the very first column which was the default index, as df.info() shows 5 columns from x-max to SVID; Or is there any other way I could align all the column labels in one row. Thanks for any help.
现在我如何摆脱作为默认索引的第一列，因为 df.info() 显示了从 x-max 到 SVID 的 5 列；或者有没有其他方法可以将所有列标签对齐在一行中。谢谢你的帮助。
回答by jezrael
Use reset_indexfor convert index values to column and if necessary renamecolumn:
使用reset_index了转换指数值列，并在必要时rename柱：
df = df.reset_index().rename(columns={'subVoyageID':'SVID'})
回答by miradulo
That's because subVoyageIDisn't a column, it is your index. Just use reset_index()to make it an actual column.
那是因为subVoyageID它不是列，而是您的索引。只是reset_index()用来使它成为一个实际的列。
Example
例子
>>> df
a b c
myindex
0 0 1 2
1 3 4 5
2 6 7 8
>>> df.reset_index().rename(columns={df.index.name: 'not my index'})
not my index a b c
0 0 0 1 2
1 1 3 4 5
2 2 6 7 8
