R chron times() 函数不起作用

Question

我正在尝试将时间转换为自午夜以来的秒数。我很难从 chron 包中获取 times() 函数来工作。这是我的使用方法：

> library(chron)
> 24 * 24 * 60 * (times(50))
Error in 24 * 24 * 60 * (times(50)) : 
  non-numeric argument to binary operator
> 
>  
> library(chron)
> 24 * 24 * 60  times(5000)
Error: unexpected symbol in "24 * 24 * 60  times"

有什么建议吗？

更新：

> sessionInfo()
R version 2.14.0 (2011-10-31)
Platform: i386-pc-mingw32/i386 (32-bit)

locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] RODBC_1.3-3        nnet_7.3-1         doSNOW_1.0.3       foreach_1.3.0     
[5] codetools_0.2-8    iterators_1.0.3    snow_0.3-7         randomForest_4.6-2
[9] chron_2.3-42      

loaded via a namespace (and not attached):
[1] tools_2.14.0

更新 2：

> find("times")
[1] "package:foreach" "package:chron"  
> times
function (n) 
{
    if (!is.numeric(n) || length(n) != 1) 
        stop("n must be a numeric value")
    foreach(icount(n), .combine = "c")
}
<environment: namespace:foreach>

更新 3：

> sessionInfo()
R version 2.14.0 (2011-10-31)
Platform: i386-pc-mingw32/i386 (32-bit)

locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] chron_2.3-42
> find("times")
[1] "package:chron"
> 24 * 24 * 60 * (times * (50))
Error in times * (50) : non-numeric argument to binary operator

Answer 1

问题是 package:foreach 还包含一个名为 times 的函数。由于它出现在搜索路径上的 package:chron 之前，因此它“掩盖”了您实际需要的 times 函数。

换句话说，当 R 对符号 times 执行动态搜索时，它会在找到与您想要的函数关联的匹配项之前找到匹配项（在本例中是错误的匹配项）寻找。

您可以通过启动一个新的 R 会话，然后输入以下内容来查看这一点：

> library(chron)
> library(foreach)
Loading required package: iterators
Loading required package: codetools
foreach: simple, scalable parallel programming from Revolution Analytics
Use Revolution R for scalability, fault tolerance and more.
http://www.revolutionanalytics.com

Attaching package: ‘foreach’

The following object(s) are masked from ‘package:chron’:

    times

如果您确实需要附加两个包，则可以确保获得正确版本的times()通过以下任一方法： 颠倒软件包的附加顺序（可以，但不太好）；或者（更好）通过输入 chron::times 明确指定您想要的函数，如下所示：

24 * 24 * 60 * (chron::times(50))