如何从以字符为日期的变量中删除时间字段字符串？ [英] How to remove time-field string from a date-as-character variable?

问题描述

假设我有这样的变量

c<-c("9/21/2011 0:00:00",  "9/25/2011 0:00:00",  "10/2/2011 0:00:00",  
"9/28/2011 0:00:00",  "9/27/2011 0:00:00")

什么是删除所有的快速方法0:00:00 s

c
[1] "9/21/2011" "9/25/2011" "10/2/2011" "9/28/2011" "9/27/2011"

推荐答案

您可以将它们转换为日期，然后根据需要设置格式，例如：

You can turn them into dates and then format as desired, e.g.:

v <- c("9/21/2011 0:00:00",  "9/25/2011 0:00:00",  "10/2/2011 0:00:00",  
     "9/28/2011 0:00:00",  "9/27/2011 0:00:00")
v <- format(as.POSIXct(v,format='%m/%d/%Y %H:%M:%S'),format='%m/%d/%Y')
> v
[1] "09/21/2011" "09/25/2011" "10/02/2011" "09/28/2011" "09/27/2011"

或者，您只需删除 0:00:00 子字符串使用gsub：

Or, you can simply remove the " 0:00:00" substring using gsub:

v <- gsub(x=v,pattern=" 0:00:00",replacement="",fixed=T)
> v
[1] "9/21/2011" "9/25/2011" "10/2/2011" "9/28/2011" "9/27/2011"

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