Read a time series table using read.zoo - r

Question

I've looked all over the place, but I can't find where this question has been asked before.
What is a clean way to get this data into a proper zoo series? This version is a copy/paste to make this post easier, but it will always come in the following table form (from a text file). My read.zoo() statement reads the Year as the index but the quarters (Qtr1, Qtr2, etc) are read as column names. I've been trying to figure out a non-garbage way to read the columns as the "quarter" part of the index, but it's sloppy (too sloppy to post). I'm guessing this problem has already been solved, but I can't find it.
> texinp <- "
+ Year Qtr1 Qtr2 Qtr3 Qtr4
+ 1992 566 443 329 341
+ 1993 344 212 133 112
+ 1994 252 252 199 207"
> z <- read.zoo(textConnection(texinp), header=TRUE)
> z
From the as.yearqtr() documentation, the target would look like:
1992 Q1 1992 Q2 1992 Q3 1992 Q4 1993 Q1 1993 Q2 1993 Q3 1993 Q4
566 443 329 341 344 212 133 112
1994 Q1 1994 Q2 1994 Q3 1994 Q4
252 252 199 207

Answer 1

Read in the data using read.zoo and then convert it to a zooreg object with yearqtr time index:
texinp <- "Year Qtr1 Qtr2 Qtr3 Qtr4
1992 566 443 329 341
1993 344 212 133 112
1994 252 252 199 207"
library(zoo)
z <- read.zoo(text = texinp, header=TRUE)
zz <- zooreg(c(t(z)), start = yearqtr(start(z)), freq = 4)
The result looks like this:
> zz
1992 Q1 1992 Q2 1992 Q3 1992 Q4 1993 Q1 1993 Q2 1993 Q3 1993 Q4 1994 Q1 1994 Q2 1994 Q3 1994 Q4
566 443 329 341 344 212 133 112 252 252 199 207

Answer 2

read.zoo assumes your data has at most one time-index column, so you have to process this yourself. First read it in using read.table
zt <- read.table( textConnection( texinp ), header = TRUE)
then convert it to a "long table" using the melt function from the reshape package:
require(reshape)
zt.m <- melt( zt, id = 'Year', variable_name = 'Qtr')
> zt.m
Year Qtr value
1 1992 Qtr1 566
2 1993 Qtr1 344
3 1994 Qtr1 252
4 1992 Qtr2 443
5 1993 Qtr2 212
6 1994 Qtr2 252
7 1992 Qtr3 329
8 1993 Qtr3 133
9 1994 Qtr3 199
10 1992 Qtr4 341
11 1993 Qtr4 112
12 1994 Qtr4 207
and finally create your desired zoo object:
z <- with( zt.m, zoo( value, as.yearqtr(paste(Year, Qtr), format = '%Y Qtr%q')))
> z
1992 Q1 1992 Q2 1992 Q3 1992 Q4 1993 Q1 1993 Q2 1993 Q3 1993 Q4 1994 Q1 1994 Q2
566 443 329 341 344 212 133 112 252 252
1994 Q3 1994 Q4
199 207