嗨,我在 R 中有一个快速的问题,
例如,我们可以将字符转换为日期
v <- c(2008101, 20081202, 20081103)
date <- as.Date(as.character(v), format("%Y%m%d"));date
但是我怎样才能转换v<- c(200801, 200802)
为2008-01
and 2008-02
?
像这样简单的东西呢:
##Give each entry a date
v = paste0(v, "01")
##Convert as before
date = as.Date(as.character(v), format("%Y%m%d"));
您甚至可以编写一个小函数来自动执行此操作:
to_date = function(v) {
v = as.character(v)
missing_day = nchar(v) < 7
v[missing_day] = paste0(v[missing_day], "01")
as.Date(v, format("%Y%m%d"))
}
##Last value is missing the date
v = c(2008101, 20081202, 20081103, 200811)
to_date(v)
这是另一种选择:
foo <- function(x){
x <- as.Date(as.character(x), format("%Y%m%d"))
newDates <- lapply(strsplit(as.character(x), "-"), "[", -2)
sapply(newDates, function(x) paste(x[1],x[2], sep="-"))
}
> foo(v)
[1] "2008-01" "2008-02" "2008-03"