Question

似乎是＆＃34; timeSeries＆＃34;长度为0的总是有两个时间戳，0和1。长度为0的向量的赋值不会导致错误消息，但时间戳的数量和值不变。将时间戳分配给自己会导致错误消息：

> library(timeSeries)

> X <- timeSeries( matrix(0:3,2,2) )

> setTime(X) <- timeSequence(as.Date("2015-01-01"),as.Date("2015-01-02"),by=as.difftime(1,units="days"))

> # ---------------------
> # As exspected:
> 
> head(X,2)
GMT
           SS.1 SS.2
2015-01-01    0    2
2015-01-02    1    3

> getTime(head(X,2))
GMT
[1] [2015-01-01] [2015-01-02]

> nrow(head(X,2))
[1] 2

> length(getTime(head(X,2)))
[1] 2

> # ---------------------
> # As exspected:
> 
> head(X,1)
GMT
           SS.1 SS.2
2015-01-01    0    2

> getTime(head(X,1))
GMT
[1] [2015-01-01]

> nrow(head(X,1))
[1] 1

> length(getTime(head(X,1)))
[1] 1

> # ---------------------
> # Not as exspected:
> 
> head(X,0)
GMT
     SS.1 SS.2

> getTime(head(X,0))
[1] 1 0

> nrow(head(X,0))
[1] 0

> length(getTime(head(X,0)))
[1] 2

> #====================================
> 
> X0 <- head(X,0)

> # Try to assign a vector of length 0 to time(X0):
> setTime(X0) <- integer(0)

> getTime(X0)  # no success, but neither error nor warning
[1] 1 0

> #Try to assign current value of time(X0) to itself:
> setTime(X0) <- getTime(X0)
Error: Initialize timeSeries : length of '@positions' not equal to '@.Data' extent

这是＆＃34; timeSeries＆＃34;包装

Answer 1

来自＆＃34; timeSeries＆＃34;的文档。包我们了解到＆＃34; getTime＆＃34;是＆＃34; time＆＃34;的同义词。因此我一直在寻找该函数的源代码：

> getMethod("time",signature=c(x="timeSeries"))
Method Definition:

function (x, ...) 
.time.timeSeries(x, ...)
<environment: namespace:timeSeries>

Signatures:
        x           
target  "timeSeries"
defined "timeSeries"

所以我们需要另一个函数的源代码，＆＃34; .time.timeSeries＆＃34;，它只在＆＃34; timeSeries＆＃34;内部使用。包：

> getAnywhere(".time.timeSeries")
A single object matching ‘.time.timeSeries’ was found
It was found in the following places
  package:timeSeries
  namespace:timeSeries
with value

function (x, ...) 
{
    if (length(x@positions) > 0) 
        timeDate(x@positions, zone = "GMT", FinCenter = x@FinCenter)
    else seq.int(NROW(x))
}
<environment: namespace:timeSeries>
>

我们在这里看到了这个错误。＆＃34; seq.int（NROW（X））＆＃34;是序列1，...，NROW（x）

以1为步长，如果NROW（x）> = 1，但
，步长为-1，如果NROW（x）<1。

因此，在这种特殊情况下，时间序列的长度为0，＆＃34;时间＆＃34;是序列＆＃34; c（1,0）＆＃34;。可以解决这个问题如下：

seq.int(1,NROW(x),length.out=NROW(x))

给出相当正确的值＆＃34;整数（0）＆＃34;如果＆＃34; NROW（x）＆＃34;是0。

来自timeSeries包的长度为0的时间序列具有可疑的时间戳

1 个答案: