[R] setting up zoo objects from a data frame

[Gabor Grothendieck]

The first time I posted this it got held up for approval so I am
trying it again.  Hopefully this time it gets through right away.

As with your prior post we can use read.zoo(..., split=...).
Alternatives are reshape and reshape::cast.


# read data into DF

Lines <- "V1   V2
1 1/1/2000  dog
2 1/1/2000  cat
3 1/1/2000 tree
4 1/2/2000  cat
5 1/2/2000 tree
6 1/3/2000  dog
7 1/3/2000 tree"

DF <- read.table(textConnection(Lines), header = TRUE)
DF$V1 <- as.Date(DF$V1, "%m/%d/%Y")

# 1. using zo

library(zoo)
d <- read.zoo(cbind(DF, 1), split = 2)
do.call(merge, c(d, fill = 0))

# 2. using reshape

DF2 <- with(DF, data.frame(Date = V1, V2, 1))
r <- reshape(DF2, dir = "wide", idvar = "Date", timevar = "V2")
colnames(r) <- c("Date", sub("X1.", "", colnames(r))[-1])
r[is.na(r)] <- 0
r

#  3. using the reshape package (where DF2 is as in #2)

library(reshape)
cast(formula = Date ~ V2, data = DF2, value = "X1", fill = 0)