CODEWITHSUNDEEP
rxtszoo
gabriel
gabriel

Reputation: 399

Setting specific time period value in xts/zoo dataset

Trying to generate a third variable, called "var", to the dataset that only has a value of 100 for the date "2010-09-24" and NA for all other time periods. 

> dataset
           weight
2010-10-04  52495
2010-10-01  53000
2010-09-30  52916
2010-09-29  52785
2010-09-28  53348
2010-09-27  52885
2010-09-24  52174
2010-09-23  51461
2010-09-22  51286
2010-09-21  50968
2010-09-20  49250
> dataset=merge(dataset,var=NA)

I know I could I use the ifelse(index(dataset)=="2010-09-24",100,NA) to generate the variable. But are there any functions that one could employ to restrict the sample only to "2010-09-24" and then place the value in that right column and row?

Upvotes: 1

Views: 648

Answers (2)

Oreotrephes
Oreotrephes

Reputation: 457

I haven't seen merge() used this way before, and the command isn't working for me. So maybe I'm misunderstanding the question or missing something about timeseries data, but I'd do this:

1: add a new vector of NAs

dataset$var<-NA

2: index to the date you want and save the value of 100 to the variable var

dataset[dataset$date=="24-09-2010","var"]<-100

Is that what you're looking for?

Upvotes: 2

Dirk is no longer here
Dirk is no longer here

Reputation: 368181

Yes -- If you use a data type with proper time indexing such as zoo or xts.

Have a look here at SO at previous questions on these two, and/or read the vignettes in the zoo package.

Upvotes: 1

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