使用 df 列中的值从另一个 df 中查找名称

Question

我有 2 个数据框；

import pandas as pd

data1 = {"name": ["a","b","c","d","e"], "value": [0.01,0.02,0.03,0.04,0.05]}

df1 = pd.DataFrame (data1, columns = ['name', 'value'])

data2 = {"value": [0.01,0.03,0.05]}

df2 = pd.DataFrame (data2, columns = ['value'])

我想使用 df2 中的值从 df1 中查找其对应的名称，并将其添加为新列。 即以这个df结束：

data3 = {"value": [0.01,0.03,0.05], "name": ["a","c","e"]}

df3 = pd.DataFrame (data3, columns = ['value', 'name'])

Answer 1

这里是 go：

print(df2.merge(df1, on='value'))

Output：

   value name
0   0.01    a
1   0.03    c
2   0.05    e

Answer 2

您可以在此处使用pd.Series.isin并将其用作boolean indexing中的掩码。

df1[df1['value'].isin(df2['value'])]

  name  value
0    a   0.01
2    c   0.03
4    e   0.05