pandas Python 熊猫：“无法将 DataFrame 与 <class 'str'> 类型的实例合并”
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Python pandas: "can not merge DataFrame with instance of type <class 'str'>"
提问by William Feirie
I have two df: df_jan_2001and df_feb_2001. I would like to do a full outer join by using this syntax:
我有两个 df:df_jan_2001和df_feb_2001. 我想使用以下语法进行完整的外部联接：
new_df = pd.merge('df_jan2001', 'df_feb2001', how='outer', left_on=
['designation', 'name'], right_on=['designation', 'name'])
designationand nameare both string variables.
designation和name都是字符串变量。
Why do I get the following error and how can I fix it?
为什么会出现以下错误，我该如何解决？
"ValueError: can not merge DataFrame with instance of type <class 'str'>"
Sorry if this is a basic question, just getting started with pandas.
对不起，如果这是一个基本问题，刚刚开始使用Pandas。
回答by William Feirie
YOU can try like this.
你可以这样试试。
new_df = pd.merge(df_jan2001, df_feb2001, how='outer', left_on=['designation', 'name'], right_on=['designation', 'name'])
回答by Utopia
Try using new_df = pd.merge(df_jan2001.to_frame(), df_feb2001.to_frame(), how='outer', left_on=['designation', 'name'], right_on=['designation', 'name'])
尝试使用 new_df = pd.merge(df_jan2001.to_frame(), df_feb2001.to_frame(), how='outer', left_on=['designation', 'name'], right_on=['designation', 'name'])
回答by jezrael
There is problem 'df_jan2001'is string, df_jan2001is here DataFrame.
有问题'df_jan2001'是string，df_jan2001就在这里DataFrame。
If columns are same in both DataFrames, use parameter ononly:
如果两个DataFrames 中的列相同，则on仅使用参数：
new_df = pd.merge(df_jan2001, df_feb2001, how='outer', on=['designation', 'name'])
