pandas 保留数据框熊猫中的特定列

Question

提问by cottinR

I have a dataframe from an import csv using pandas. This dataframe has 160 variables and I would like to keep only 5, 9, 10, 46, 89.

我有一个来自使用 Pandas 的导入 csv 的数据框。这个数据框有 160 个变量，我只想保留 5、9、10、46、89。

I try this:

我试试这个：

dataf2 = dataf[[5] + [9] + [10] + [46] + [89]]

but I take this error:

但我接受这个错误：

KeyError: '[ 5 9 10 46 89] not in index'

Answer 1

If you want to refer to columns not by their names but by their positions in the dataset, you need to use df.iloc:

如果您不想通过名称而是通过它们在数据集中的位置来引用列，则需要使用df.iloc：

dataf.iloc[:, [5, 9, 10, 46, 89]]

Row indices are specified before the comma, column indices are specified after the comma.

逗号前指定行索引，逗号后指定列索引。

Answer 2

If the columns that you would like to keep are: 5, 9, 10, 46, 89, then you can index just these ones like so:

如果您想保留的列是: 5, 9, 10, 46, 89，那么您可以像这样索引这些列：

dataf2 = dataf[[5, 9, 10, 46, 89]]