Question

I’m trying to convert a time to seconds since midnight. I’m having a hard time getting the times() function from the chron package to work. Here’s how I’m using it:

> 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"

Any suggestions?

UPDATE:

> 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

UPDATE 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>

UPDATE 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

The problem is that package:foreach also contains a function named times. And because it appears before package:chron on your search path, it ‘masks’ the times function that you actually want.

In other words, when R performs its dynamic search for the symbol times, it finds a match (the wrong one in this case) before it gets to the one associated with the function you’re intending it to find.

You can see this by starting a fresh R session, and then typing:

> 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.
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Attaching package: ‘foreach’

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

    times

If you do need both packages attached, you can ensure that you get the right version of times() by either: reversing the order in which the packages are attached (OK but not great); or (better) explicitly specifying which function you want by typing chron::times, as in:

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