[R] coding logic and syntax in R
Eric Lecoutre
lecoutre at stat.ucl.ac.be
Wed Dec 24 09:09:58 CET 2003
In R, always begin to try to obtain result on a little unit.
Begin to make a function that will make replacements for ONE vector (of size 9)
FillWith=function(vec,SearchForOne=0,ReplaceNextValues=0)
{
pp=which(vec==SearchForOne)
if (length(pp)>0) vec[pp:length(vec)]=ReplaceNextValues
return(vec)
}
Verify it works:
> FillWith(c(1,1,0,1,1))
[1] 1 1 0 0 0
Then try to apply it with your data, using one of the ?apply functions.
Here, tapply seems to be adequate.
> data=c(rep(1,9),rep(1,4),0,rep(1,4))
> data
[1] 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1
> data=cbind(data,groups=((1:length(data)-1)%/%9))
> data
data groups
[1,] 1 0
[2,] 1 0
[3,] 1 0
[4,] 1 0
[5,] 1 0
[6,] 1 0
[7,] 1 0
[8,] 1 0
[9,] 1 0
[10,] 1 1
[11,] 1 1
[12,] 1 1
[13,] 1 1
[14,] 0 1
[15,] 1 1
[16,] 1 1
[17,] 1 1
[18,] 1 1
> tapply(data[,1],data[,2],FUN=FillWith)
$"0"
[1] 1 1 1 1 1 1 1 1 1
$"1"
[1] 1 1 1 1 0 0 0 0 0
And then come back to a vector with unlist().
Eric
At 08:27 24/12/2003, Pravin wrote:
>Hello,
>
>
>I am a beginner in R programming and recently heard about this mailing list.
>Currently, I am trapped into a simple problem for which I just can't find a
>solution. I have a huge dataset (~81,000 observations) that has been
>analyzed and the final result is in the form of 0 and 1(one column).
>
>I need to write a code to process this column in a little complicated way.
>
>These 81,000 observations are actually 9,000 sets (81,000/9).
>
>So, in each set whenever zero appears, rest all observations become zero.
>
>For example;
>If the column has:
>111110111111011111111111111111111....
>The output should look like:
>111110000111000000111111111111111...
>I hope this makes sense.
>Thank you in anticipation,
>
>Pravin
>
>Pravin Jadhav
--------------------------------------------------
L'erreur est certes humaine, mais un vrai désastre
nécessite un ou deux ordinateurs. Citation anonyme
--------------------------------------------------
Eric Lecoutre
Informaticien/Statisticien
Institut de Statistique / UCL
TEL (+32)(0)10473050 lecoutre at stat.ucl.ac.be
URL http://www.stat.ucl.ac.be/ISpersonnel/lecoutre
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