根据列名中的DF选择列

Question

df_new = df_source[["A_1", "B_1"]]
if 'A_2' in df_new.columns:
    # Also add A_2, B_2 columns in df_new, but I don't know how to add the columns to the created df_new.

df_new = df_source[["A_1", "B_1"]]
if 'A_2' in df_new.columns:
  df_new = df_source[["A_1", "B_1", "A_2", "B_2"]]

您可以这样的东西，您可以使用其他列表

first_list =[1,2,3,4,5,6] filter_list=[] for item in first_list: if item % 2 ==0: filter_list.append(item)

Answer 1