Format date as Year/Quarter
date, r
Solution
You need to explicilty `Vectorize` your function:
fun_v <- Vectorize(fun, "x")
fun_v(Data$date)
#[1] "01/01" "01/01" "01/01" "01/02" "01/02" "01/02"
However, when it comes to more or less standard tasks (such as datetime manipulations), there's always a solution already available:
library(zoo)
yq <- as.yearqtr(Data$date, format = "%Y-%m-%d")
yq
#[1] "2001 Q1" "2001 Q1" "2001 Q1" "2001 Q2" "2001 Q2" "2001 Q2"
To convert to your specific format, use
format(yq, format = "%y/0%q")
#[1] "01/01" "01/01" "01/01" "01/02" "01/02" "01/02"
Problem
I have the following dataframe: ``` Data <- data.frame( date = c("2001-01-01", "2001-02-01", "2001-03-01", "2001-04-01", "2001-05-01", "2001-06-01"), qtr = c("NA", "NA","NA","NA","NA","NA") ) ``` I want to fill Data$qtr with Year/Quarter - f.e. 01/01 (I need this format!). I wrote a function: ``` fun <- function(x) { if(x == "2001-01-01" | x == "2001-02-01" | x == "2001-03-01") y <- "01/01" if(x == "2001-04-01" | x == "2001-05-01" | x == "2001-06-01") y <- "01/02" return(y) } n$qtr <- sapply(n$date, fun) ``` But it does not work. I always get the error message: ``` Error in FUN(X[[1L]], ...) : Object 'y' not found ``` Why?