CODEWITHSUNDEEP
pythonpandasdataframe
JesusMonroe
JesusMonroe

Reputation: 1601

Pandas - set value in row to itself multiplied by another value

Let's say I have the following table:

multiply   total   tax
Y          500     .1
Y          250     .5
N          300     .5

I want to set the total to total * tax only if the value of multiply is Y

Final output:

multiply   total   tax
Y          50      .1
Y          125     .5
N          300     .5

Upvotes: 1

Views: 176

Answers (4)

Quickbeam2k1
Quickbeam2k1

Reputation: 5437

It can be done like that

df.loc[df['multiply'] == 'Y', 'total'] = df.loc[df['multiply'] == 'Y', 'total'] * df.loc[df['multiply'] == 'Y', 'tax']

Another approach using pandas where and assign could be:

df.where(df['multiply'] == 'N', df.assign(total = df['total'] * df['tax']))

Outputs:

    multiply    total   tax
0   Y           50      0.1
1   Y           125     0.5
2   N           300     0.5

Upvotes: 1

mad_
mad_

Reputation: 8273

df=pd.DataFrame({'multiply':['Y','Y','N'],'total':[500,250,300],'tax':[.1,.5,.5]})
def myfunc(row):
    if(row[0]=='Y'):
        return float(row[1])*float(row[2])
    return row[2]
df['total']=df.apply(lambda x: myfunc(x),axis=1)
df

Output

multiply   tax  total
0   Y      0.1  50.0
1   Y      0.5  125.0
2   N      0.5  300.0

Upvotes: 1

user96564
user96564

Reputation: 1607

use np.where

df['total'] = np.where(df['multiply'] == 'Y', df['total'] * df['tax'], df['total'])
print(df)

multiply  total  tax
       Y   50.0  0.1
       Y  125.0  0.5
       N  300.0  0.5

Upvotes: 4

ℕʘʘḆḽḘ
ℕʘʘḆḽḘ

Reputation: 19375

here we go buddy

df.loc[df.multiply == 'Y', 'total'] = df.loc[df.multiply == 'Y', 'total'] * df.loc[df.multiply == 'Y', 'tax']

Upvotes: 1

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