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Simple For Loop Help

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arun.gurubaramurugeshan

Simple For Loop Help

Hi,
I need help with the following.

I have a dataset Y with 200 observations and three variables Y1, Y2 & Y3. I have to find the minimum of Y1, Y2 & Y3 and if the minimum is Y1 then I have to assign 1 to a variable (Y4), if Y2 is the minimum then "2" to Y4 else "3" to Y4. This is what I have done....

for (i in 1:200) if(Y1<Y2 & Y1<Y3) Y$Y4=1 else if (Y2<Y3) Y$Y4=2 else Y$Y4=3

and R is throwing back this warning message

Warning messages:
1: In if (Y1 < Y2 & Y1 < Y3) Y4 <- 1 else if (Y2 < Y3) Y4 <- 2 else Y4 <- 3 :
the condition has length > 1 and only the first element will be used
2: In if (Y2 < Y3) Y4 <- 2 else Y4 <- 3 :
the condition has length > 1 and only the first element will be used

Any help would be appreciated.

Thanks
Arun

J Toll

Re: Simple For Loop Help

On Thu, Mar 29, 2012 at 4:32 PM, arun.gurubaramurugeshan
<[hidden email]> wrote:

> Hi,
> I need help with the following.
>
> I have a dataset Y with 200 observations and three variables Y1, Y2 & Y3. I
> have to find the minimum of Y1, Y2 & Y3 and if the minimum is Y1 then I have
> to assign 1 to a variable (Y4), if Y2 is the minimum then "2" to Y4 else
> "3" to Y4. This is what I have done....
>
> for (i in 1:200) if(Y1<Y2 & Y1<Y3) Y$Y4=1 else if (Y2<Y3) Y$Y4=2
> else Y$Y4=3
>
> and R is throwing back this warning message
>
> Warning messages:
> 1: In if (Y1 < Y2 & Y1 < Y3) Y4 <- 1 else if (Y2 < Y3) Y4
> <- 2 else Y4 <- 3 :
> the condition has length > 1 and only the first element will be used
> 2: In if (Y2 < Y3) Y4 <- 2 else Y4 <- 3 :
> the condition has length > 1 and only the first element will be used
>
> Any help would be appreciated.
>
> Thanks
> Arun
>
> --
> View this message in context: http://r.789695.n4.nabble.com/Simple-For-Loop-Help-tp4517088p4517088.html
> Sent from the R help mailing list archive at Nabble.com.

Arun,

I think you want something along the lines of:

> x <- matrix(rnorm(30), nrow = 10)
> x
[,1] [,2] [,3]
[1,] -2.1650589 1.94859071 -0.45721676
[2,] -1.4667920 2.34222583 1.17776076
[3,] -0.2807439 0.09512075 0.61303958
[4,] -0.1449027 0.56009407 1.03240104
[5,] 0.9955293 0.85945217 -0.06094224
[6,] 0.6380514 -0.49667348 0.12532813
[7,] -0.4096329 -0.96153212 -0.44399899
[8,] -0.5364318 -0.62121738 -1.42266665
[9,] -0.7713245 -0.69132827 -0.48067279
[10,] 1.0515935 0.47035874 -1.17460809
> x <- cbind(x, apply(x, 1, function(row) which(row == min(row))))
> x
[,1] [,2] [,3] [,4]
[1,] -2.1650589 1.94859071 -0.45721676 1
[2,] -1.4667920 2.34222583 1.17776076 1
[3,] -0.2807439 0.09512075 0.61303958 1
[4,] -0.1449027 0.56009407 1.03240104 1
[5,] 0.9955293 0.85945217 -0.06094224 3
[6,] 0.6380514 -0.49667348 0.12532813 2
[7,] -0.4096329 -0.96153212 -0.44399899 2
[8,] -0.5364318 -0.62121738 -1.42266665 3
[9,] -0.7713245 -0.69132827 -0.48067279 1
[10,] 1.0515935 0.47035874 -1.17460809 3

HTH,

James

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

jholtman

Re: Simple For Loop Help

In reply to this post by arun.gurubaramurugeshan

tyr this:

> # generate some data
> x <- cbind(y1 = runif(100)
+ , y2 = runif(100)
+ , y3 = runif(100)
+ )
>
> x <- cbind(x, y4 = apply(x, 1, which.min))
> x
y1 y2 y3 y4
[1,] 0.976953289 0.91072645970 0.713624001 3
[2,] 0.630992512 0.49545109738 0.492651173 3
[3,] 0.805360855 0.10164273344 0.487412602 2
[4,] 0.206557258 0.93518137769 0.967720379 1
[5,] 0.742643551 0.01508265687 0.184230089 2
[6,] 0.273187587 0.96277903509 0.975695134 1
[7,] 0.531257896 0.28845930938 0.884927711 2
[8,] 0.443350543 0.83843108499 0.932529126 1
[9,] 0.741068321 0.18445303664 0.918877386 2
[10,] 0.702316870 0.33005132875 0.873039624 2
[11,] 0.344680035 0.01381954318 0.317793813 2
[12,] 0.458753836 0.87229841063 0.744396384 1
[13,] 0.843603048 0.54047069070 0.450843775 3
[14,] 0.409279518 0.63338707620 0.776766221 1
[15,] 0.352133089 0.50061018439 0.807262663 1
[16,] 0.560342140 0.45078424131 0.885666004 2

On Thu, Mar 29, 2012 at 5:32 PM, arun.gurubaramurugeshan
<[hidden email]> wrote:

--
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Giovanni Petris

Re: Simple For Loop Help

In reply to this post by arun.gurubaramurugeshan

Hi Arun,

This seems to do what you are looking for:

> Y <- matrix(rnorm(12), 4, 3)
> Y
[,1] [,2] [,3]
[1,] -1.0457177 0.7756343 -0.06063478
[2,] -0.8962113 1.5573704 -0.50137832
[3,] 1.2693872 -0.3654018 0.92606273
[4,] 0.5938409 0.8165564 0.03693769
> X <- apply(Y, 1, which.min)
> X
[1] 1 1 2 3

HTH,
Giovanni

Quoting "arun.gurubaramurugeshan" <[hidden email]>:

> Hi,
> I need help with the following.
>
> I have a dataset Y with 200 observations and three variables Y1, Y2 & Y3. I
> have to find the minimum of Y1, Y2 & Y3 and if the minimum is Y1 then I have
> to assign 1 to a variable (Y4), if Y2 is the minimum then "2" to Y4 else
> "3" to Y4. This is what I have done....
>
> for (i in 1:200) if(Y1<Y2 & Y1<Y3) Y$Y4=1 else if (Y2<Y3) Y$Y4=2
> else Y$Y4=3
>
> and R is throwing back this warning message
>
> Warning messages:
> 1: In if (Y1 < Y2 & Y1 < Y3) Y4 <- 1 else if (Y2 < Y3) Y4
> <- 2 else Y4 <- 3 :
> the condition has length > 1 and only the first element will be used
> 2: In if (Y2 < Y3) Y4 <- 2 else Y4 <- 3 :
> the condition has length > 1 and only the first element will be used
>
> Any help would be appreciated.
>
> Thanks
> Arun
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Simple-For-Loop-Help-tp4517088p4517088.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

arun.gurubaramurugeshan

Re: Simple For Loop Help

Dr. Petris,
Thank you so much for your help. I appreciate it. I am still learning R!

Thanks
Arun