(Newbie) Functions on vectors
You can use ifelse but even better note that the zoo package has the yearqtr class which represents years and quarters internally as years + (qtr-1)/4 where qtr is 0,1,2,3 so as to be consistent with ts class. It also has an as.Date.yearqtr method which will convert them to class Date. Using these the code is really just one line: # test data year <- 2001:2004 qtr <- 1:4 library(zoo) as.Date(as.yearqtr(year + qtr/4), frac = 1)
On 2/17/06, Vivek Satsangi <vivek.satsangi at gmail.com> wrote:
Folks,
I want to make the following function more efficient, by vectorizing it:
getCriterionDecisionDate <- function (quarter , year)
{
if (length(quarter) != length(year)) stop ("Quarter and year vectors
of unequal length!");
ret <- character(0);
for (i in 1:length(quarter)) {
currQuarter <- quarter[i];
currYear <- year[i];
if ((currQuarter < 1) | (currQuarter > 4)) stop ("Invalid quarter!");
if ((currYear < 1986) | (currYear > 2004)) stop ("Invalid year!");
# If the criterion date is 1Q2004, then the reports were for periods
# ending in Feb, March and April 2004 and the decision date is July 1, 2004.
if (currQuarter == 1) {
ret <- c(ret,paste("06/30/",currYear,sep=""));
} else if (currQuarter == 2) {
ret <- c(ret,paste("09/30/",currYear,sep=""));
} else if (currQuarter == 3) {
ret <- c(ret,paste("12/31/",currYear,sep=""));
} else if (currQuarter == 4) {
ret <- c(ret,paste("3/31/",currYear+1,sep=""));
}
}
ret;
}
How can I make the 'if' statements work on vectors rather than using
one value at a time? (sorry, my copy of MASS is at home).
--
-- Vivek Satsangi
Student, Rochester, NY USA
______________________________________________ R-help at stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html