[R] CONFUSSING WITH select[!miss] <- 1:sum(!miss)
greg holly
mak.hholly at gmail.com
Wed Dec 7 15:22:21 CET 2016
Hi Jim, Rui and William;
I do appreciate for your explanations and help. These are very helpful.
Regards,
Hayrettin
On Tue, Dec 6, 2016 at 4:06 PM, Jim Lemon <drjimlemon at gmail.com> wrote:
> Hi Greg,
> What is happening is easy to see:
>
> ph<-matrix(sample(1:100,40),ncol=4)
> colnames(ph)<-c("M1","X1","X2","X3")
> ph[sample(1:10,3),1]<-NA
> ph
> M1 X1 X2 X3
> [1,] 34 98 3 35
> [2,] 13 66 74 68
> [3,] NA 22 99 79
> [4,] 94 6 80 36
> [5,] 18 9 16 65
> [6,] NA 29 56 90
> [7,] 41 23 7 55
> [8,] 100 93 71 70
> [9,] NA 61 8 57
> [10,] 25 4 47 60
> # get a logical vector showing which rows contain NA
> miss <- apply(is.na(ph[,c("M1","X1","X2","X3")]),1, any)
> miss
> [1] FALSE FALSE TRUE FALSE FALSE TRUE FALSE FALSE TRUE FALSE
> # create a vector of zeros the length of the number of rows
> select <- integer(nrow(ph))
> select
> [1] 0 0 0 0 0 0 0 0 0 0
> # get the indices for the rows that do _not_ have NAs
> select[!miss] <- 1:sum(!miss)
> select
> [1] 1 2 0 3 4 0 5 6 0 7
>
> If this is to select the rows without NAs, it may be easier to do:
>
> which(!miss)
> [1] 1 2 4 5 7 8 10
>
> Jim
>
>
>
> On Wed, Dec 7, 2016 at 5:18 AM, greg holly <mak.hholly at gmail.com> wrote:
> > Dear All;
> >
> > I am very new in R and try to understand the logic for a program has been
> > run sucessfully. Here select[!miss] <- 1:sum(!miss) par is confussing
> me. I
> > need to understandand the logic behind this commend line.
> >
> > Thanks in advance for your help,
> >
> > Greg
> >
> >
> > miss <- apply(is.na(ph[,c("M1","X1","X2","X3")]),1, any)
> > select <- integer(nrow(ph))
> > select[!miss] <- 1:sum(!miss)
> >
> > [[alternative HTML version deleted]]
> >
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