CODEWITHSUNDEEP
pythonpandasmultiple-columnssuffix
ARJ
ARJ

Reputation: 2080

How to append a suffix for specific column names of a dataframe from a list

I wanted to append a suffix or prefix to certain column names of df1 based on the names in df2. my df1 looks like this,

AE02    AE03    AE04    AE05    AE06    AE07    AE08    AE09    AE10    AE11    AE12
11.9619362364   18.5701402709   42.2010838789   28.0025053738   19.5589170223   18.1459582989   16.5292369479   32.4885640738   34.0342144643   31.6971000153   44.932255488
2.9904840591    3.9793157723    0   0   1.7780833657    1.7281865047    13.7743641233   4.3318085432    0   17.067669239    0
0   0   0   0   2.6671250485    0   4.5914547078    0   0   0   2.1396312137

and df2 looks like,

 V1
AE06
AE08    
AE09
AE12

I could replace those column name with new name as follows,

colnames(df1)[which(colnames(df1) %in% df2$V1 )] <- "DMR"

But I am looking for a solution where I can append as prefix to the column name instead of replacing it, for instance, my column names should like this,

AE02    AE03    AE04    AE05    DMR_AE06    AE07    DMR_AE08    DMR_AE09    AE10    AE11    DMR_AE12

Any suggestions and help is well apreciated

Upvotes: 3

Views: 4139

Answers (2)

Laurens Koppenol
Laurens Koppenol

Reputation: 3106

with list comprehension in Python:

df.columns = ['DMR_{}'.format(x) if x in df2.V1.values else x for x in df.columns]

Upvotes: 1

jezrael
jezrael

Reputation: 863301

Pandas solution:

You can use numpy.where with mask by Index.isin:

print (df.columns.isin(df2.V1))
[False False False False  True False  True  True False False  True]

df.columns = np.where(df.columns.isin(df2.V1), 'DMR_' + df.columns, df.columns)
print (df)
        AE02       AE03       AE04       AE05   DMR_AE06       AE07  \
0  11.961936  18.570140  42.201084  28.002505  19.558917  18.145958   
1   2.990484   3.979316   0.000000   0.000000   1.778083   1.728187   
2   0.000000   0.000000   0.000000   0.000000   2.667125   0.000000   

    DMR_AE08   DMR_AE09       AE10       AE11   DMR_AE12  
0  16.529237  32.488564  34.034214  31.697100  44.932255  
1  13.774364   4.331809   0.000000  17.067669   0.000000  
2   4.591455   0.000000   0.000000   0.000000   2.139631

Upvotes: 7

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