CODEWITHSUNDEEP
rxts
toddleR
toddleR

Reputation: 101

How to convert numeric year month to year-month-day date format in xts?

I want to convert df to xts with year end-of-month date index (i.e., 1989-12-31). I searched web but without answers. Thanks and appreciate your help. 

df <- read.table(textConnection("
date    a     b      c     d 
198912 29.46 13.47 32.52 22.06 
199001 36.35 17.30 38.14 24.98 
199002 33.72 15.57 38.14 23.61 
199003 30.76 14.01 34.74 21.73 
"),header=T)

Upvotes: 3

Views: 1772

Answers (2)

mnel
mnel

Reputation: 115392

Use the yearmon class and then as.Date.yearmon to quote from help('yearmon'):

as.Date.yearmon and as.yearmon.yearqtr each has an optional second argument of "frac" which is a number between 0 and 1 inclusive that indicates the fraction of the way through the period that the result represents. The default is 0 which means the beginning of the period.

as.Date(as.yearmon(as.character(df$date), format = '%Y%m'), frac=1)
## [1] "1989-12-31" "1990-01-31" "1990-02-28" "1990-03-31"

Upvotes: 4

thelatemail
thelatemail

Reputation: 93813

And for laughs, here is a base R method, which is admittedly quite ugly:

Reduce(c,
 lapply(
  as.Date(paste0("1-",as.character(df$date)),format="%d-%Y%m"),
  function(x) seq.Date(x,length=2,by="1 month")[2] - 1
 )
)

[1] "1989-12-31" "1990-01-31" "1990-02-28" "1990-03-31"

Upvotes: 3

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