R/time.functions.R

In jobonaf/pesco: Data fusion for air quality data

Hour   <- function(x,tz="Africa/Algiers") as.numeric(format(as.POSIXct(x, tz=tz), format="%H"))

Month  <- function(x,tz="Africa/Algiers") as.numeric(format(as.POSIXct(x, tz=tz), format="%m"))

Year   <- function(x,tz="Africa/Algiers") as.numeric(format(as.POSIXct(x, tz=tz), format="%Y"))

Ymd    <- function(x,tz="Africa/Algiers") as.numeric(format(as.POSIXct(x, tz=tz), format="%Y%m%d"))

Ym     <- function(x,tz="Africa/Algiers") as.numeric(format(as.POSIXct(x, tz=tz), format="%Y%m"))

YQ     <- function(x,tz="Africa/Algiers") paste(Year(x,tz=tz),quarters(x),sep="")

Ndays  <- function(x,tz="Africa/Algiers") length(unique(Ymd(x,tz=tz)))

Nmonths<- function(x,tz="Africa/Algiers") length(unique(Ym(x,tz=tz)))

Ndays.in.year <- function(year,tz="Africa/Algiers") {
  nd <- length(seq(as.POSIXct(paste(year,"-01-01",sep=""),tz=tz),
                   as.POSIXct(paste(year,"-12-31",sep=""),tz=tz),
                   by="1 days"))
  return(nd)
}

tz.change <- function(x,tz.in="UTC",tz.out="Africa/Algiers") {
  time.txt <- format(x, format="%Y-%m-%d %H:%M:%S")
  time.out <- as.POSIXct(time.txt, tz=tz.in)
  attributes(time.out)$tzone <- tz.out
  return(time.out)
}