重命名列后如何合并 pandas 数据框？

Question

I have a code that merged 2 dataframes that had all columns in uppercase. I need to adjust the code to merge the dataframes but now 1 comes with columns in lowercase and the other doesn't.

I wrote the following code to change the columns names to lowercase, and then changed the merge to lowercase also, but no i get a Key error: 'code'

df_small = df_small.rename(columns=str.lower)
common = df_small.merge(df_big,on=['code'])

Answer 1

First to 'lower' the column names you can use:

df_small.columns = df_small.columns.str.lower()

I think that your code for lowercasing the column names is doing something wrong. Try mine above