pandas iterrows overwriting values

Question

I tried to use iterrows as a command to deal with the frame.

stocks2['Startpoint']=0
for index,row in stocks2.iterrows():
    if row['VOL']>4*row['avg'] and row['RET']< -0.02 :
        row['Startpoint']=1

I know that the condition is met several times, but it does not seem to overwrite successfully the value in that case.

stocks2['Startpoint'].value_counts()

Out[141]: 0 1588603 Name: Startpoint, dtype: int64

because .iterows returns an iterator over pd.Series objects representing the rows of your data-frame, but mutating those pd.Series objects will not affect the original pd.DataFrame — juanpa.arrivillaga
– juanpa.arrivillaga, Commented Nov 11, 2018 at 18:34

BENY · Accepted Answer · 2018-11-11 18:27:57Z

1

No need for loop , You can do with

stocks2['Startpoint']=((stocks2['VOL']>4*stocks2['ave'])&(stocks2['RET']<0.2)).astype(int)

answered Nov 11, 2018 at 18:27

BENY

324k22 gold badges176 silver badges250 bronze badges

Sign up to request clarification or add additional context in comments.

1 Answer 1