python - 返回包含附加列的 pandas 数据框

Question

我有一个数据帧列表，我想创建一个新的数据帧列表，该列表与前一个数据帧列表相同，但使用函数方法添加了一个列。

这是我的想法和我的尝试:

# I know this is possible. It will add a new column of True.
df['new_column'] = True

# However, it edits the dataframe, I want a functional approach that returns a new modified dataframe.
# Something like this.
df + ('new_column', True)

# Then I can use it in list comprehension. consider dfs is a list of dataframes.
[df + ('new_column', True) for df in dfs]

Answer 1

使用assign()方法:

[df.assign(new_column = True) for df in dfs]