问题描述
我有一个尝试使用 Reduce 的日期列表，并意识到组合向量时小时数正在更改。下面是一个示例：
I have a list of dates that I was trying to use Reduce on and realized that the hours were being changed when I combined the vectors. Here's an example:
x = structure(1315714440, tzone = "UTC", class = c("POSIXct", "POSIXt"))
y = structure(1325832660, tzone = "UTC", class = c("POSIXct", "POSIXt"))
x
[1] "2011-09-11 04:14:00 UTC"
y
[1] "2012-01-06 06:51:00 UTC"
c(x,y)
[1] "2011-09-11 00:14:00 EDT" "2012-01-06 01:51:00 EST"
为什么会这样呢？
谢谢！
推荐答案
c.POSIXct 删除时区属性。从？c.POSIXct ：
因此，请遵循 c（x，y ），则可以使用 attr 恢复原始的 UTC 时区：
Thus, following your c(x,y), you may restore the original UTC time zone using attr:
xy <- c(x, y)
attr(xy, "tzone") <- "UTC"
xy
# [1] "2011-09-11 04:14:00 UTC" "2012-01-06 06:51:00 UTC"
Ripley的更多背景信息：
More background by Ripley here:
c（a，b）吗？
如果所有
都使用 c（）保留时区，我们认为对象，但主要问题是记录了 c（）可以删除
属性：
"We considered having c() retain the timezone if it was common to all theobjects, but the main issue was that c() was documented to removeattributes:
因此，有时删除和保留属性会使
感到困惑。
So, sometimes removing and sometimes retaining attributes was going tobe confusing.
但是无论如何，文档（？c.POSIXct ）很清楚：
But in any case, the documentation (?c.POSIXct) is clear:
因此，建议的方法是，如果知道所需的
，则添加 tzone 属性就是这样。 POSIXct 对象是绝对时间：时区
仅影响它们的转换方式（包括打印字符）。
So the recommended way is to add a "tzone" attribute if you know whatyou want it to be. POSIXct objects are absolute times: the timezonemerely affects how they are converted (including to character for printing)."
作为， rbind 可以作为解决方法：
As noted by @aosmith, rbind can be used as work-around:
这篇关于结合POSIXct给错误的时间的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！