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

[arun]

Hi,


library(reshape2)
 dcast(tmp.n,X1~X2,value.var="Y")
 # X1   0  2  4
#1  0  83 12 14
#2  1 107 25 27
#3  2  47 14 28
#4  3  27  4 13
#5  4  38  9 18
#6 99   1  0  0
A.K.


----- Original Message -----
From: "plessthanpointohfive at gmail.com" <plessthanpointohfive at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Monday, March 18, 2013 1:44 PM
Subject: [R] Loop or some other way to parse by data generated values when it is not linear

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

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