R help - Mar 2013 - create vector from indices interpolated values

Readers,

Is it possible to create a plot command based upon the indices of
missing values in a data set?

dataset1<-read.table(text='
10 2
20 NA
30 5
40 7
50 NA
60 NA
70 2
80 6
90 NA
100 9
')

dataset2<-read.table(text='
0.2
0.4
0.1
0.9
0.2
0.3
1.1
0.7
0.9
0.6
0.4
')

The 'approx' function is used to obtain the interpolated values for
'NA' in dataset1.

dataset1interpolatedvalues<-approx(dataset1,y=NULL,xout=dataset1$V1[is.na(dataset1$V2)])

dataset1interpolatedvalues
$x
[1] 20 50 60 90

$y
[1] 3.500000 5.333333 3.666667 7.500000

x<-dataset1interpolatedvalues$y

How to create a vector 'y' by selecting the values in 'dataset2'
using
the indices equivalent to interpolated values in 'dataset1' (i.e.
indices 2, 5, 6, 9 in dataset1)? The result of creating 'y' should be

y
0.4
0.2
0.3
0.9

Then the desired plot would be

plot(y~x)

Thanks.

--
r2151

Hi

maybe

index <- which(is.na(dataset1$V2))
y <- dataset2$V1[index]
plot(y~x)

Regards
Petr

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of e-letter
> Sent: Thursday, March 07, 2013 8:28 AM
> To: r-help at r-project.org
> Subject: [R] create vector from indices interpolated values
> 
> Readers,
> 
> Is it possible to create a plot command based upon the indices of
> missing values in a data set?
> 
> dataset1<-read.table(text='
> 10 2
> 20 NA
> 30 5
> 40 7
> 50 NA
> 60 NA
> 70 2
> 80 6
> 90 NA
> 100 9
> ')
> 
> dataset2<-read.table(text='
> 0.2
> 0.4
> 0.1
> 0.9
> 0.2
> 0.3
> 1.1
> 0.7
> 0.9
> 0.6
> 0.4
> ')
> 
> The 'approx' function is used to obtain the interpolated values for
> 'NA' in dataset1.
> 
> dataset1interpolatedvalues<-
> approx(dataset1,y=NULL,xout=dataset1$V1[is.na(dataset1$V2)])
> 
> dataset1interpolatedvalues
> $x
> [1] 20 50 60 90
> 
> $y
> [1] 3.500000 5.333333 3.666667 7.500000
> 
> x<-dataset1interpolatedvalues$y
> 
> How to create a vector 'y' by selecting the values in
'dataset2' using
> the indices equivalent to interpolated values in 'dataset1' (i.e.
> indices 2, 5, 6, 9 in dataset1)? The result of creating 'y' should
be
> 
> y
> 0.4
> 0.2
> 0.3
> 0.9
> 
> Then the desired plot would be
> 
> plot(y~x)
> 
> Thanks.
> 
> --
> r2151
> 
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