On Fri, Mar 26, 2010 at 4:15 PM, Matthew Dowle wrote:
> The type of 'NA' is logical. So x[NA] behaves more like x[TRUE] i.e. silent
> recycling.
>
>> class(NA)
> [1] "logical"
>> x=101:108
>> x[NA]
> [1] NA NA NA NA NA NA NA NA
>> x[c(TRUE,NA)]
> [1] 101 NA 103 NA 105 NA 107 NA
>
>> x[as.integ
On Fri, Mar 26, 2010 at 4:15 PM, Bert Gunter wrote:
> Is this, from the man page, relevant?
>
> "An empty index selects all values: this is most often used to replace all
> the entries but keep the attributes. "
No, I think that means doing "x[]", and only in replacement:
> x=101:105
> attr(x,"
-boun...@r-project.org] On
Behalf Of Barry Rowlingson
Sent: Friday, March 26, 2010 5:10 AM
To: r-help@r-project.org
Subject: [R] NA values in indexing
If you index a vector with a vector that has NA in it, you get NA back:
> x=101:107
> x[c(NA,4,NA)]
[1] NA 104 NA
> x[c(4,NA)]
[1] 104 NA
Try
> x <- 101:107
> x[c(NA_integer_, NA_integer_)]
[1] NA NA
On Fri, Mar 26, 2010 at 8:09 AM, Barry Rowlingson
wrote:
> If you index a vector with a vector that has NA in it, you get NA back:
>
> > x=101:107
> > x[c(NA,4,NA)]
> [1] NA 104 NA
> > x[c(4,NA)]
> [1] 104 NA
>
> All well and
The type of 'NA' is logical. So x[NA] behaves more like x[TRUE] i.e. silent
recycling.
> class(NA)
[1] "logical"
> x=101:108
> x[NA]
[1] NA NA NA NA NA NA NA NA
> x[c(TRUE,NA)]
[1] 101 NA 103 NA 105 NA 107 NA
> x[as.integer(NA)]
[1] NA
HTH
Matthew
"Barry Rowlingson" wrote in message
news
If you index a vector with a vector that has NA in it, you get NA back:
> x=101:107
> x[c(NA,4,NA)]
[1] NA 104 NA
> x[c(4,NA)]
[1] 104 NA
All well and good. ?"[" says, under NAs in indexing:
When extracting, a numerical, logical or character ‘NA’ index
picks an unknown element
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