CODEWITHSUNDEEP
python-3.xpandas
madeinQuant
madeinQuant

Reputation: 1813

Please comment how to do that in pandas correctly

In order to calculate the 'RS' column. Implemented a for loop in python to calculate the 'RS' column. Please comment how to do that in pandas correctly.

Expected result

  Date         Adj Close         Change     RS
    2017-11-30    253.94            NaN         100.00
    2017-12-01    253.41           -0.208711    99.791289
    2017-12-04    253.11           -0.118385    99.672904
    2017-12-05    252.19           -0.363478    99.309426
    2017-12-06    252.24            0.019826    99.329252

Incorrect statement

baselinedf['RS'] = baselinedf['Change'] + baselinedf['RS'].shift(-1)

Correct but inappropriate

baseValue=100
x=0
for i in baselinedf.index:
  if x>0 : 
     baseValue=baselinedf.loc[i,'Change']+baseValue
     baselinedf.loc[i,'RS']=baseValue
  x = x + 1

Upvotes: 0

Views: 47

Answers (1)

Henry Yik
Henry Yik

Reputation: 22503

IIUC you are looking for cumsum:

df["new"] = 100+df["Change"].fillna(0).cumsum()

print (df)

         Date  Adj Close    Change          RS         new
0  2017-11-30     253.94       NaN  100.000000  100.000000
1  2017-12-01     253.41 -0.208711   99.791289   99.791289
2  2017-12-04     253.11 -0.118385   99.672904   99.672904
3  2017-12-05     252.19 -0.363478   99.309426   99.309426
4  2017-12-06     252.24  0.019826   99.329252   99.329252

Upvotes: 3

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