Dear all,
I am having a data stucture that contains Products and Time Stamps,
 
I have made also two lists
ProductList=list(c('Example1','Example2'...)
TimeStamp=list(c("1990-02-03 12:57:60"),c("1990-02-03 12:57:60"),
 
then I have made few functions that call each other
 
do_analysis_for_all the data<-function(arguments){
   .....
   return(lapply(ProductList,do_analysis_for_one_product_list_for_all_time_stamps)
}
 
do_analysis_for_one_product_list_for_all_time_stamps<-function(arguments){
    ....
   return(lapply(TimeStamps,do_analysis_for_one_product_list_for_one_time_stamps)
}
 
(this is mostly just an algorithm to show you the main logic).
 
 
as one is getting down to the chain I have described, there are functions that chop the data as requested. For example for a specific TimeFram one will get the entries that correspond to the specific dates.
 
The problem I have though is that sometimes (is not too often) there are no entries for a specific interval and thus the next function will rely on the "chopped" data will explode with an error.
 
I want to ask you for a clear solution to handle this cases
 
I have two ideas in mind
 
a). I change all the function in my code so to check that the input argument is empty (how to do that?) and in that case I return an empty list
 
b) I change nothing to the code and I ask kindly from the R in that case to return a lovely error message (Best is to find it saved in the list that lapply returns) and continue to the next case. I have tried earlier to add the try(myfunction,silent=TRUE) but I ended up changing all my code with the try(..) which of course is a bit of "dirty" solution. Do you know if I can ask "globally" R (perhaps add some directive in the beginning of my file) to handle all these errors in a silent manner so to skip them. 
 
What should I try to a or b and why?
 
I would like to thank you in advance for your time spent to read this email
 
B.R
 
Alex
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