Modify values of a subset data range in xts using R

Question

I am using quantmod and downloading values of a stock using getSymbols. I found that the data in the source itself is incorrect for a range of dates. Unfortunately the data is not available in google.

stock <- 'RELIANCE.BO'
getSymbols(stock)
stockAdjusted <- adjustOHLC(RELIANCE.BO, adjust = c("split","dividend"), use.Adjusted = FALSE, ratio = NULL)
stockAdjusted <- stockAdjusted[!(apply(stockAdjusted, 1, function(y) any(y == 0))),]

The price values for for 2008-07-29 to 2008-08-14 are half of what they should be. How can I correct the values for this range of dates?

Answer 1

You can access the data for a given date range and column by using normal indexing with [. To get, say, the column RELIANCE.BO.Adjusted for the date range 2008-07-29 to 2008-08-14, you can simply write:

stockAdjusted["2008-07-29/2008-08-14", "RELIANCE.BO.Adjusted"] 
##            RELIANCE.BO.Adjusted
## 2008-07-29             961.0422
## 2008-07-30             996.9914
## 2008-07-31            1016.8096
## 2008-08-01            1059.9302
## 2008-08-04            1033.5398
## 2008-08-05            1048.9796
## 2008-08-06            1058.1328
## 2008-08-07            1046.8594
## 2008-08-08            1037.1992
## 2008-08-11            1072.0240
## 2008-08-12            1079.5088
## 2008-08-13            1078.8912
## 2008-08-14            1048.6570

As with data frames, you can use indexing also to make assignments. To multiply the column RELIANCE.BO.Adjusted by 2 only for the requested date range, you can do the following:

stockAdjusted["2008-07-29/2008-08-14", "RELIANCE.BO.Adjusted"] <- stockAdjusted["2008-07-29/2008-08-14", "RELIANCE.BO.Adjusted"] * 2