检测data.frame中的列是否为.POSIXct的可靠方法 [英] Reliable way to detect if a column in a data.frame is.POSIXct
本文介绍了检测data.frame中的列是否为.POSIXct的可靠方法的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
R具有 is.vector
, is.list
, is.integer
, is.double
, is.numeric
, is.factor
, is.character
等.为什么没有 is.POSIXct
, is.POSIXlt
或 is.Date
?
R has is.vector
, is.list
, is.integer
, is.double
, is.numeric
, is.factor
, is.character
, etc. Why is there no is.POSIXct
, is.POSIXlt
or is.Date
?
我需要一种可靠的方法来检测 POSIXct
对象,并且 class(x)[1] =="POSIXct"
似乎真的很脏.
I need a reliable way to detect POSIXct
object, and class(x)[1] == "POSIXct"
seems really... dirty.
推荐答案
I would personally just use inherits
as joran suggested. You could use it to create your own is.POSIXct
function.
# functions
is.POSIXct <- function(x) inherits(x, "POSIXct")
is.POSIXlt <- function(x) inherits(x, "POSIXlt")
is.POSIXt <- function(x) inherits(x, "POSIXt")
is.Date <- function(x) inherits(x, "Date")
# data
d <- data.frame(pct = Sys.time())
d$plt <- as.POSIXlt(d$pct)
d$date <- Sys.Date()
# checks
sapply(d, is.POSIXct)
# pct plt date
# TRUE FALSE FALSE
sapply(d, is.POSIXlt)
# pct plt date
# FALSE TRUE FALSE
sapply(d, is.POSIXt)
# pct plt date
# TRUE TRUE FALSE
sapply(d, is.Date)
# pct plt date
# FALSE FALSE TRUE
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