R help - Jan 2018 - a vector unusually getting NA values.....

dear members,

                             I have a function by name "ygcudf" and a
list of stock names by name"snl" ( of class "list"). ygcudf
acts on snl and returns a list of the most favourable  stocks. I don't wish
to divulge the code of the function, for genuine reasons, but the algorithm is
as follows:

        {

        k <- 1; i <- 1



       for(j in 1:length(snl)){

                                 if(snl[[j]] == "condition") {

                                       k[i] <- j

                                        i <- i+1}

                                             }

        snlf1 <- snl[k]

        return(snlf1)

}


The problem is, if we test the function by returning the vector k, it, (k), is
getting NA values. i.e, instead of skipping the values of j for which the
condition is false, k is getting populated by NA values. k is getting the
following values (for a given snl):

        k

[1]    1 NA NA NA 5 6 NA NA 9 10 11 NA NA NA NA 16


If j is initialised to the values for which k is NA, and the function is  made
to return j, it is returning the relevant j. I don't know how the k is
getting NA values. Will the following change work:

      snlf1 <-  snl[na.omit(k)]


What is wrong ??


Sorry for not parting with the code...please bear with me....

your help will be highly appreciated


yours sincerely,

AKSHAY M KULKARNI

	[[alternative HTML version deleted]]

On 20/01/2018 6:53 AM, akshay kulkarni wrote:
> dear members,
> 
>                               I have a function by name "ygcudf"
and a list of stock names by name"snl" ( of class "list").
ygcudf acts on snl and returns a list of the most favourable  stocks. I
don't wish to divulge the code of the function, for genuine reasons, but the
algorithm is as follows:
> 
>          {
> 
>          k <- 1; i <- 1
> 
> 
> 
>         for(j in 1:length(snl)){
> 
>                                   if(snl[[j]] == "condition") {
> 
>                                         k[i] <- j
> 
>                                          i <- i+1}
> 
>                                               }
> 
>          snlf1 <- snl[k]
> 
>          return(snlf1)
> 
> }
> 
> 
> The problem is, if we test the function by returning the vector k, it, (k),
is getting NA values. i.e, instead of skipping the values of j for which the
condition is false, k is getting populated by NA values. k is getting the
following values (for a given snl):
Try this:

k <- 1
k[5] <- 5
k

and you should see what's happening.

Duncan Murdoch
> 
>          k
> 
> [1]    1 NA NA NA 5 6 NA NA 9 10 11 NA NA NA NA 16
> 
> 
> If j is initialised to the values for which k is NA, and the function is 
made to return j, it is returning the relevant j. I don't know how the k is
getting NA values. Will the following change work:
> 
>        snlf1 <-  snl[na.omit(k)]
> 
> 
> What is wrong ??
> 
> 
> Sorry for not parting with the code...please bear with me....
> 
> your help will be highly appreciated
> 
> 
> yours sincerely,
> 
> AKSHAY M KULKARNI
> 
> 	[[alternative HTML version deleted]]
> 
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