How do I go from image #1 to #2 in R ?
I would expect this transformation to be so common in timeseries analysis that xts::, zoo:: or data.table:: would have a pre-built routine to make the series "indexed" (note the Index in red in the second image) automagically with a one-liner.
I can manually do this looping/apply-ing over the columns but want to learn if there is a pre-baked solution to this (expectedly very common) dataframe transformation.
This question is somewhat similar. The upvoted solution uses a rather intricate
do.call(rbind, lapply(lst, `length<-`, max(lengths(lst)))))
that I would like to avoid.
Image #1:
Image #2:
Image 1
sample data.frame as requested:
df <- data.frame(Date = seq(from=as.Date("2010-01-01"), to=as.Date("2010-02-15"), by=1),
`2008/09` = c(rnorm(10), rep(NA,36)),
`2009/10` = c(rep(NA, 3), rnorm(10), rep(NA, 33)),
`2010/11` = c(rep(NA, 5), rnorm(10), rep(NA, 31)),
`2011/12` = c(rep(NA, 10), rnorm(11), rep(NA, 25))
)