Hello,
You're insisting in as.data.frame(cbind(...)). Don't do that. Just see
the difference:
z = data.frame(x, y)
str(z)
'data.frame': 8 obs. of 2 variables:
$ x: Factor w/ 3 levels "a","b","c": 1 1 1 2 2 2 3 3
$ y: num 1 1.2 1.1 1.01 1.03 1 2 3
z2 = as.data.frame(cbind(x,y))
str(z2)
'data.frame': 8 obs. of 2 variables:
$ x: Factor w/ 3 levels "a","b","c": 1 1 1 2 2 2 3 3
$ y: Factor w/ 7 levels "1","1.01","1.03",..: 1 5 4 2 3 1 6 7
What happens is that cbind creates a matrix from x and y, converting all
to character, and y is no longer numeric. Then as.data.frame converts
the strings to factors, the default behavior.
As for your question, change fun() to the following.
fun <- function(z){
zs <- split(z, x)
n <- length(zs)
m <- sapply(zs, nrow)
id <- unlist(sapply(m, seq_len))
zz <- cbind(id, z)
dcast(zz, id ~ x)[-1]
}
Hope this helps,
Rui Barradas
Em 04-08-2013 20:34, Brijesh Gulati escreveu:
Hello Rui: Thanks for the solution. It does work to the specification. Just
one follow-up. I get an error if the number of repeating values are
different. For instance, in the following example, "c" is repeated only 2
times; whereas "a" and "b" three times. I am fine with the output shows NA
for the missing values. Any help would be greatly appreciated.
x = c("a","a", "a", "b","b","b", "c", "c")
y = c(1.0, 1.2, 1.1, 1.01, 1.03, 1.0, 2.0, 3.0)
z = as.data.frame(cbind(x,y))
x y
1 a 1
2 a 1.2
3 a 1.1
4 b 1.01
5 b 1.03
6 b 1
7 c 2
8 c 3
-----Original Message-----
From: Rui Barradas [mailto:ruipbarra...@sapo.pt]
Sent: Sunday, August 04, 2013 1:57 PM
To: Brijesh Gulati
Cc: r-help@r-project.org
Subject: Re: [R] question: data.frame data conversion
Hello,
First of all, do _not_ create a data frame with
as.data.frame(cbind(...))
Instead, use
z = data.frame(x, y)
As for your question, try the following.
library(reshape2)
fun <- function(z){
zs <- split(z, x)
n <- length(zs)
m <- nrow(zs[[1]])
zz <- cbind(id = rep(1:m, n), z)
dcast(zz, id ~ x)[-1]
}
fun(z)
Hope this helps,
Rui Barradas
Em 04-08-2013 13:49, Brijesh Gulati escreveu:
Hello, I have a data.frame with repeating rows and corresponding
value. For instance, "z" will be an example of that.
x = c("a","a", "a", "b","b","b")
y = c(1.0, 1.2, 1.1, 1.01, 1.03, 1.0)
z = as.data.frame(cbind(x,y))
z
x y
1 a 1
2 a 1.2
3 a 1.1
4 b 1.01
5 b 1.03
6 b 1
So, you see that "a" and "b" are repeated 3 times and have three
different value. I would like to convert this data into something like the
following.
a b
1.0 1.01
1.2 1.03
1.1 1.00
In the above, repeating rows (a,b) become columns and their values
show up in their respective column.
Finally, to clarify few things. The number of rows of each repeating
item (a or b) would be the same and hence, the number of row expected
in the output shall be the same.
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