Keep other variables when executing get_dummies in Pandas

Question

I have a DataFrame with an ID variable and another categorical variable. I want to create dummy variables out of the categorical variable with get_dummies.

dum = pd.get_dummies(df)

However, this makes the ID variable disappear. And I need this ID variable later on to merge to other data sets.

Is there a way to keep other variables. In the documentation of get_dummies I could not find anything. Thanks!

Answer 1

您还可以在执行 get_dummies 之前将原始列复制到新列中。例如，

df['dum_orig'] = df['dum']
df = pd.get_dummies(df, columns=['dum'])

Answer 2

我找到了答案。您可以将虚拟数据集连接到原始数据集，如下所示。只要您在此期间不重新排序数据即可。

df = pd.concat([df, dum], axis=1)