[R] Assignment of values with different indexes

Pascal Oettli kridox at ymail.com
Thu Dec 6 04:01:45 CET 2012


Hello,

I am sorry, but I sincerely don't understand what you are trying to do.

Regards,
Pascal

Le 06/12/2012 11:47, Brian Feeny a écrit :
>
> I would like to take the values of observations and map them to a new index.  I am not sure how to accomplish this.  The result would look like so:
>
> x[1,2,3,4,5,6,7,8,9,10]
> becomes
> y[2,4,6,8,10,12,14,16,18,20]
>
> The "newindex" would not necessarily be this sequence, but a sequence I have stored in a vector, so it could be all kinds of values.  here is what happens:
>
>> x <- rnorm(10)
>> myindex <- seq(from = 1,to = 20, by = 2)
>> y <- numeric()
>> y[myindex] <- x
>> y
>   [1] -0.03745988          NA -0.09078822          NA  0.92484413          NA  0.32057426          NA
>   [9]  0.01536279          NA  0.02200198          NA  0.37535438          NA  1.46606535          NA
> [17]  1.44855796          NA -0.05048738
>
> So yes, it maps the values to my new indexes, but I have NA's.  The result I want would look like this instead:
>
>
>   [1] -0.03745988
>   [3] -0.09078822
>   [5] 0.92484413
>   [7] 0.32057426
>   [9]  0.01536279
>   [11] 0.02200198
>   [13] 0.37535438
>   [15] 1.46606535
>   [17]  1.44855796
>   [19] -0.05048738
>
>
> and remove the NA's.  I tried this with na.omit() on x, but it looks like so:
>
>> x <- rnorm(10)
>> myindex <- seq(from = 1,to = 20, by = 2)
>> y <- numeric()
>> y[myindex] <- na.omit(x)
>> y
>   [1]  0.87399523          NA -0.39908184          NA  0.14583051          NA  0.01850755          NA
>   [9] -0.47413632          NA  0.88410517          NA -1.64939190          NA  0.57650807          NA
> [17]  0.44016971          NA -0.56313802
>
> Brian
>
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