CODEWITHSUNDEEP
pythonpandas
user3222101
user3222101

Reputation: 1330

How to check if value exists in another dataframe in pandas?

I have a dataframe below that contains mapping between french to english

df1 

french english
ksjks  an
sjk    def
ssad   sdsd

And another dataframe columns are in french so need to convert them into english by using df1

df2

ksjks sjk ssad
2     4    6

how can we achieve that?

new_cols = []
for col in df2.columns:
    if col in df1['french']:
             how to get corresponding english value

PS: Have just put random data in for sample

Upvotes: 1

Views: 1993

Answers (2)

Veera Samantula
Veera Samantula

Reputation: 165

df_lookup= pd.DataFrame({"French":["ksjks","sjk","ssad"],"english": 
["an","def","sdsd"]})

df_actual=pd.DataFrame({"ksjks":[2],"sjk":[4],"ssad":[6]})

df_actual.columns=[ df_lookup.loc[df_lookup.loc[df_lookup["French"]== 
col].index[0],"english"] for col in df_actual.columns]

Upvotes: 0

user3483203
user3483203

Reputation: 51185

Option 1
Use map with set_index

df2.columns = df2.columns.map(df1.set_index('french').english)
print(df2)

Option 2
Use rename with set_index:

df2.rename(columns=df1.set_index('french').english.to_dict())

Both produce:

   an  def  sdsd
0   2    4     6

Order of the columns doesn't matter:

df1 = pd.DataFrame({'french': ['un', 'deux', 'trois'], 'english': ['one', 'two', 'three']})
df2 = pd.DataFrame([[1,2,3]], columns=['trois', 'deux', 'un'])

df2.rename(columns=df1.set_index('french').english.to_dict())

   three  two  one
0      1    2    3

df2.columns.map(df1.set_index('french').english)
# Index(['three', 'two', 'one'], dtype='object')

Upvotes: 2

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