R-将不同的日期格式强制转换为一种格式

我导入了一个凌乱的电子表格，我想在R中处理它。有一个日期字段，它可能以三种方式出现在任意位置的任意顺序：

---

文本为ddt只需再次添加类，这也避免了警告：

ddt <- "2018-01-01"
ddn <- 43101
dde <- "43102"

dd <- c(ddt,ddn,dde)

coerce.Date <- function (dateVar, origin = "1900-01-01", format = "%Y-%m-%d"){
  if(!identical(grep("^[[:digit:]]*$", dateVar), integer(0))){
    out <- as.Date(as.numeric(dateVar),origin = origin, format = format)
  } else {
    out <- as.Date(dateVar, origin = origin, format = format)
  }
  return(out)
}

myDates <- lapply(dd, coerce.Date)

class(myDates) <- "Date"

myDates

dd <- c(ddt,ddn,dde)

dates <- lapply(dd,coerce.Date)

str(dates)

List of 3
 $ : Date[1:1], format: "2018-01-01"
 $ : Date[1:1], format: "2018-01-04"
 $ : Date[1:1], format: "2018-01-03"

unlist(dates)

[1] 17532 17535 17534

dates <- tibble(dates)

unnest (dates)

# A tibble: 3 x 1
  dates        
  <date>   
1 2018-01-01
2 2018-01-04
3 2018-01-03

ddt <- "2018-01-01"
ddn <- 43101
dde <- "43102"

dd <- c(ddt,ddn,dde)

coerce.Date <- function (dateVar, origin = "1900-01-01", format = "%Y-%m-%d"){
  if(!identical(grep("^[[:digit:]]*$", dateVar), integer(0))){
    out <- as.Date(as.numeric(dateVar),origin = origin, format = format)
  } else {
    out <- as.Date(dateVar, origin = origin, format = format)
  }
  return(out)
}

myDates <- lapply(dd, coerce.Date)

class(myDates) <- "Date"

myDates