如何将两个方程的最大值输入 pandas dataframe 列？

Question

I am trying to input into new column of dataframe maximum result of two equations based on different columns. Unfortunately I am having below error. How should I change the code to make it work (I would like to stay with pandas library in this case)?

Prc1	Prc2	Price
1.5	2.5

df['Price'] = max(((df['Prc1'] - df['Prc2']) / df['Prc1']).abs(), ((df['Prc1'] - df['Prc2']) / ['Prc2']).abs())

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all()

Answer 1

Use numpy.maximum :

s = df['Prc1'] - df['Prc2']
df['Price'] = np.maximum((s / df['Prc1']).abs(), (s / df['Prc2']).abs())

Another idea with divide from right side by DataFrame.rdiv :

df['Price'] = df[['Prc1','Prc2']].rdiv(df['Prc1'].sub(df['Prc2']), axis=0).abs().max(axis=1)

---

df = pd.DataFrame({'Prc1':[1,2,5], 'Prc2':[-5,8,-20]})


s = df['Prc1'] - df['Prc2']
df['Price1'] = np.maximum((s / df['Prc1']).abs(), (s / df['Prc2']).abs())
df['Price2'] = df[['Prc1','Prc2']].rdiv(df['Prc1'].sub(df['Prc2']),axis=0).abs().max(axis=1)
print (df)
   Prc1  Prc2  Price1  Price2
0     1    -5     6.0     6.0
1     2     8     3.0     3.0
2     5   -20     5.0     5.0