返回帶有附加列的大熊貓數據框

Question

我有一個數據框列表，我想創建一個新的數據框列表，它與前一個列表相同，但使用功能方法添加列。

這是我的想法和我已經試過：

# 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] 

Answer 2

您可以使用.assign()方法在功能的方式來創建額外的列新的數據幀：

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