pandas 组合2个数据帧（加入公共列）

问题描述

我有2个数据框：

restaurant_ids_dataframe

restaurant_ids_dataframe

Data columns (total 13 columns):
business_id      4503  non-null values
categories       4503  non-null values
city             4503  non-null values
full_address     4503  non-null values
latitude         4503  non-null values
longitude        4503  non-null values
name             4503  non-null values
neighborhoods    4503  non-null values
open             4503  non-null values
review_count     4503  non-null values
stars            4503  non-null values
state            4503  non-null values
type             4503  non-null values
dtypes: bool(1), float64(3), int64(1), object(8)`

和

restaurant_review_frame

restaurant_review_frame

Int64Index: 158430 entries, 0 to 229905
Data columns (total 8 columns):
business_id    158430  non-null values
date           158430  non-null values
review_id      158430  non-null values
stars          158430  non-null values
text           158430  non-null values
type           158430  non-null values
user_id        158430  non-null values
votes          158430  non-null values
dtypes: int64(1), object(7)

我想加入这两个DataFrames，使用Pandas中的DataFrame.join（）命令将它们变成一个数据框。

I would like to join these two DataFrames to make them into a single dataframe using the DataFrame.join() command in pandas.

我尝试了以下代码行：

#the following line of code creates a left join of restaurant_ids_frame and   restaurant_review_frame on the column 'business_id'
restaurant_review_frame.join(other=restaurant_ids_dataframe,on='business_id',how='left')

但是当我尝试这个时，我得到以下错误：

But when I try this I get the following error:

Exception: columns overlap: Index([business_id, stars, type], dtype=object)

对于大熊猫来说，我很新，并且不知道执行连接语句时我做错了什么。

I am very new to pandas and have no clue what I am doing wrong as far as executing the join statement is concerned.

任何帮助将不胜感激。

推荐答案

您可以使用 / strong>将两个数据框合并成一个：

You can use merge to combine two dataframes into one:

import pandas as pd
pd.merge(restaurant_ids_dataframe, restaurant_review_frame, on='business_id', how='outer')

其中在指定存在于两个数据帧中的字段名称，如何
定义其内/外/左/右连接，外部使用两个框架的键的并集（SQL：全外连接）。由于在两个数据帧中都有星号列，默认情况下将在组合数据帧中创建两列star_x和star_y。作为@DanAllan提到的连接方法，您可以通过将其作为kwarg传递来修改用于合并的后缀。默认值为 suffixes =（'_ x'，'_y'）。如果你想做一些类似 star_restaurant_id 和 star_restaurant_review ，你可以这样做：

where on specifies field name that exists in both dataframes to join on, and howdefines whether its inner/outer/left/right join, with outer using 'union of keys from both frames (SQL: full outer join).' Since you have 'star' column in both dataframes, this by default will create two columns star_x and star_y in the combined dataframe. As @DanAllan mentioned for the join method, you can modify the suffixes for merge by passing it as a kwarg. Default is suffixes=('_x', '_y'). if you wanted to do something like star_restaurant_id and star_restaurant_review, you can do:

 pd.merge(restaurant_ids_dataframe, restaurant_review_frame, on='business_id', how='outer', suffixes=('_restaurant_id', '_restaurant_review'))

这些参数在这里。

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