pandas 熊猫合并的关键错误（左连接）
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Key error on pandas merge (left join)
提问by metersk
I have two dataframes below, df_purchase(1) and df_login(2)
我下面有两个数据框，df_purchase(1) 和 df_login(2)
+--------+-----+--------+------------+--------------------+-------------+--------------------------+
| | age | gender | ttp | count | sum(amount) | region |
+--------+-----+--------+------------+--------------------+-------------+--------------------------+
| 49427 | 63 | M | 824.731412 | 2 | 25.00 | Omaha, Nebraska |
| 28433 | 49 | M | 1.166250 | 2 | 41.94 | Catasauqua, Pennsylvania |
| 4162 | 29 | M | 5.620949 | 2 | 51.78 | Eagle Center, Iowa |
| 18747 | 43 | M | 153.502072 | 2 | 23.84 | Pacific, Washington |
| 45173 | 59 | M | 0.027257 | 2 | 13.98 | De Soto, Missouri |
+--------+-----+--------+------------+--------------------+-------------+--------------------------+
+--------+-----+--------+------------+--------------------+-------------+--------------------------+
| | age | gender | count | region | | |
| 671766 | 84 | M | 13900 | New York, New York | | |
| 671166 | 84 | F | 7619 | New York, New York | | |
| 672209 | 85 | F | 6483 | New York, New York | | |
| 672671 | 85 | M | 5808 | New York, New York | | |
| 195201 | 34 | M | 3817 | New York, New York | | |
+--------+-----+--------+------------+--------------------+-------------+--------------------------+
I am trying to join df_logins to df_purchase on age, gender and region with the following pandas code:
我正在尝试使用以下Pandas代码将 df_logins 加入 df_purchase 的年龄、性别和地区：
df = pd.merge(df_purchase, df_login[['count']],
how='left', on=['age', 'gender', 'region'])
However, I keep getting this error: KeyError: 'age'Any thoughts?
但是，我不断收到此错误：有KeyError: 'age'什么想法吗？
采纳答案by EdChum
The KeyError arises from this:
KeyError 来自于此：
df = pd.merge(df_purchase, df_login[['count']] <- this selects just count column,
how='left', on=['age', 'gender', 'region'])
You've specifically selected just a single column from df_login, you need this:
您只从 中专门选择了一个列df_login，您需要这样：
df = pd.merge(df_purchase, df_login,
how='left', on=['age', 'gender', 'region'])
I'm assuming that this is not your complete data as you have no common values in the age and region column in df_login.
我假设这不是您的完整数据，因为您在df_login.
