python pandas for loop add value to new column

Question

I want to add a new value for each loop in python pandas

        PRODUCT  PRICE
0    ABC       5000
1    ABB       2500
2    ABE       1800
3    DCB       7200

if df1 is like above,

for i in df1['PRICE']:
    if i>3000:
        PURCHASE = True
    else:
        PURCHESE = False

after the loop, I want to make the df1 like below

        PRODUCT  PRICE  PURCHSE
0    ABC       5000       True
1    ABB       2500       False
2    ABE       1800       False
3    DCB       7200       True

how would I do this?

Answer 1

The language of Pandas is somewhat similar to what you would use in a common conversation: the PURCHASE is when the PRICE > 3000.

df1['PURCHASE'] = df1['PRICE'] > 3000

Answer 2

Could you please try following, using np.where here.

import pandas as pd
import numpy as np
df['PURCHASE']=np.where(df2.PRICE>3000,'TRUE','FALSE')

When we print the value of new df with new column named PURCHASE its value will be as follows.

    PRODUCT PRICE PURCHASE
0   ABC 5000    TRUE
1   ABB 2500    FALSE
2   ABE 1800    FALSE
3   DCB 7200    TRUE