[R] Loop or some other way to parse by data generated values when it is not linear

[plessthanpointohfive at gmail.com]

This works really great, too.

Thanks for this option.

I am glad I have two ways to accomplish this.

I KNEW it was going to be that simple. I was convinced I was making more 
out of it than I needed to and I'm glad to see I was right.

Best,

Jen

(It's fun to be new at something when I'm this old).







On 03/18/2013 01:50 PM, Marc Schwartz wrote:
> On Mar 18, 2013, at 12:44 PM, plessthanpointohfive at gmail.com wrote:
>
>> I'm sorry for the really vague subject line but I am not sure how to succinctly describe what I am doing and what the problem is.
>>
>> But, here goes:
>>
>> 1.  I have data with two-way data with frequencies.  Below is an example, though in reality I am looking at about 10 different variables that I am crossing so the values of X1 and X2 change.  X1 and X2 are place holders.
>>
>> Here's the dataset (though using this first part does not happen in reality):
>>
>> X1 <- matrix(c(0, 1, 2, 3, 4, 99), nrow=18, ncol=1, byrow=T)
>> X2 <- sort(matrix(c(0, 2, 4), nrow=18, ncol=1, byrow=T), decreasing=F)
>> Y <- matrix(c(83, 107, 47, 27, 38, 1, 12 ,25, 14, 4, 9, 0, 14, 27, 28, 13, 18, 0), nrow=18, ncol=1, byrow=T)
>> tmp.n <- data.frame(X1, X2, Y)
>>
>> The final data frame is what I actually get:
>>
>>
>>    X1 X2   Y
>> 1   0  0  83
>> 2   1  0 107
>> 3   2  0  47
>> 4   3  0  27
>> 5   4  0  38
>> 6  99  0   1
>> 7   0  2  12
>> 8   1  2  25
>> 9   2  2  14
>> 10  3  2   4
>> 11  4  2   9
>> 12 99  2   0
>> 13  0  4  14
>> 14  1  4  27
>> 15  2  4  28
>> 16  3  4  13
>> 17  4  4  18
>> 18 99  4   0
>>
>>
>> 2.  What I want is:
>>
>>
>>          0   2   4
>> 0     83 12 14
>> 1   107 25 27
>> 2     47 14 28
>> 3     27   4 13
>> 4     38   9 18
>> 99     1   0   0
>>
>>
>> 3.  I've been trying to do it using this (which is inside a function so I can vary what variables X1 and X2 are):
>>
>>
>> X1 <- table(tmp.n[,1])
>> X2 <- table(tmp.n[,2])
>>
>> # Create the tmp.n.# datasets that contain the Y's.  Do this in a loop to automate
>> dta <- NULL
>> for (i in 0:length(X1)) {
>> assign("tmp.n_", tmp.n[tmp.n[,1] == i, c(1,3)])
>> tmp.n_ <- data.frame(tmp.n_[,2])
>> dta[i] <- assign(paste("tmp.n.", i, sep=""), tmp.n_)
>> dta
>> }
>> dta2 <- (data.frame(matrix(unlist(dta), nrow=n2[1], byrow=T)))
>> colnames(dta2) <- names(X2)
>> dta2
>>
>>
>> And that works so long as X1 and X2 are linear.  In other words, if X1 <- seq(0, 4, 1).  But that 99 throws the whole thing off and it gives me this:
>>
>>    X1 X2
>> 1 107 25
>> 2  27 47
>> 3  14 28
>> 4  27  4
>> 5  13 38
>> 6   9 18
>>
>> It's basically breaks the whole thing.
>>
>> I've not been able to figure this out and I've been like a dog with a bone trying to make it work with modifications to the for loop.  I know there is an easier way to do this, but my brain is no longer capable of thinking outside the box I've put it in.  So, I am turning to you for help.
>>
>> Best,
>>
>> Jen
>
> Something like this?
>
>> xtabs(Y ~ X1 + X2, data = tmp.n)
>      X2
> X1     0   2   4
>    0   83  12  14
>    1  107  25  27
>    2   47  14  28
>    3   27   4  13
>    4   38   9  18
>    99   1   0   0
>
> See ?xtabs
>
> Regards,
>
> Marc Schwartz
>