Question

想要更改日期格式。我的数据框如下所示，并希望将所有日期格式更改为"%d/%m/%Y"。

DF：

id    bdate       wdate        ddate
1   09/09/09    12/10/09     2009-09-27

Answer 1

df$ddate <- format(as.Date(df$ddate), "%d/%m/%Y")

Answer 2

df$ddate<-strftime(df$ddate,"%d/%m/%Y")
df$bdate<-strftime(strptime(df$bdate,"%d/%m/%y"),"%d/%m/%Y")
df$wdate<-strftime(strptime(df$wdate,"%d/%m/%y"),"%d/%m/%Y")

Answer 3

默认R操作是将字符串视为因素。当然，单个设置可能与默认设置不同。将变量值更改为character，然后将其转换为date是一种很好的做法。我经常使用chron包 - 它很好，很简单，最重要的是，它完成了工作。该软件包的唯一缺点是时区处理。

如果您没有安装chron，请执行：

 install.packages("chron")
 # load it
 library(chron)
 # make dummy data
 bdate <- c("09/09/09", "12/05/10", "23/2/09")
 wdate <- c("12/10/09", "05/01/07", "19/7/07")
 ddate <- c("2009-09-27", "2007-05-18", "2009-09-02")
 # notice the last argument, it will not allow creation of factors!
 dtf <- data.frame(id = 1:3, bdate, wdate, ddate, stringsAsFactors = FALSE)
 # since we have characters, we can do:
 foo <- transform(dtf, bdate = chron(bdate, format = "d/m/Y"), wdate = chron(wdate, format = "d/m/Y"), ddate = chron(ddate, format = "y-m-d"))
 # check the classes
 sapply(foo, class)
 # $id
 # [1] "integer"

 # $bdate
 # [1] "dates" "times"

 # $wdate
 # [1] "dates" "times"

 # $ddate
 # [1] "dates" "times"

C'est ca ...它应该做的伎俩...

将日期格式更改为“％d /％m /％Y”

3 个答案: