Conditional Calculation of Pandas Dataframe columns

Question

I have a pandas dataframe which reads

Category  Sales  
A           10
B           20

I wanna do a conditional creation of new column target

And I want my target df to look like

Category  Sales  Target 
A           10    5
B           20   10

I used the below code and it threw an error

if(df['Category']=='A'):
    df['Target']=df['Sales']-5
else:
    df['Target']=df['Sales']-10

score 5 · Accepted Answer · answered May 23 '18 at 08:29

5

Use vectorized numpy.where:

df['Target']= np.where(df['Category']=='A', df['Sales'] - 5, df['Sales'] - 10)
print (df)
  Category  Sales  Target
0        A     10       5
1        B     20      10

answered May 23 '18 at 08:29

jezrael

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Thanks @jezrael , actually I tried the same approach. But somehow I messed up with the syntax. Again thanks for helping out – Ahamed Moosa May 23 '18 at 09:05

Conditional Calculation of Pandas Dataframe columns

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