Question

我有两个大小不同的数据框。

timestamp 2018-01-01 0.0 2018-02-01 3.0有地址，没有邮政编码。 df1包含地址和邮政编码。

我正在尝试使用df2将地址从df1匹配到df2，如果匹配，请将相应的邮政编码带到np.where。

但是我刚刚意识到这不适用于不同大小的数据框。

没有邮政编码的第一个数据框：

df1

我要从中获取邮政编码的第二个数据框：

df1 = pd.DataFrame({'address1':['1 o\'toole st','2 main st','3 high street','5 foo street','10 foo street'],
                   'address2':['town1',np.nan,np.nan,'Bartown',np.nan],
                   'address3':[np.nan,'village','city','county2','county3']})
df1['zipcode']=''
print(df1)

        address1 address2 address3 zipcode
0   1 o'toole st    town1      NaN        
1      2 main st      NaN  village        
2  3 high street      NaN     city        
3   5 foo street  Bartown  county2        
4  10 foo street      NaN  county3

使用df2 = pd.DataFrame({'address1':['1 o\'toole st','2 main st','7 mill street','5 foo street','10 foo street','asda'], 'address2':['town1','village','city','Bartown','county3','efsefs'], 'address3':[np.nan,np.nan,np.nan,'county2','USA','asdasd'], 'zipcode': ['er45','qw23','rt67','yu89','yu83','aedsa']}) print(df2) address1 address2 address3 zipcode 0 1 o'toole st town1 NaN er45 1 2 main st village NaN qw23 2 7 mill street city NaN rt67 3 5 foo street Bartown county2 yu89 4 10 foo street county3 USA yu83 5 asda efsefs asdasd aedsa填充df1['zipcode']列。如果两个地址都匹配，则返回np.where，否则返回df2['zipcode']：

'no_match'

是否可以使用“ np.where”和不同大小的数据帧来做到这一点？还是有一种更好的方法来搜索匹配项并显示邮政编码？

Answer 1

您可以使用合并：

df_new = df1.merge(df2[['address1', 'zipcode']], on='address1', how='left')
df_new = df_new.fillna('no_match')

Answer 2

将Series.map与key创建的新列fillna配合使用，因为没有匹配项会丢失值，因此最后添加fillna('no_match')：

df1['key'] = df1['address1'] + df1['address2'].fillna(df1['address3'])
df2['key'] = df2['address1'] + df2['address2'].fillna(df2['address3'])

df1['zipcode'] =  df1['key'].map(df2.set_index('key')['zipcode']).fillna('no_match')

print (df1)
        address1 address2 address3                   key   zipcode
0   1 o'toole st    town1      NaN     1 o'toole sttown1      er45
1      2 main st      NaN  village      2 main stvillage      qw23
2  3 high street      NaN     city     3 high streetcity  no_match
3   5 foo street  Bartown  county2   5 foo streetBartown      yu89
4  10 foo street      NaN  county3  10 foo streetcounty3      yu83

如何在不同大小的数据帧之间使用np.where？ “操作符无法一起播放”

2 个答案: