Building factors across two columns, is this possible?

I am trying to make it so two columns with similar data use the same internal numbers for same factors, here is the example:
read.csv("test.csv",header =FALSE,sep=",")
V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000
data <- read.csv("test.csv",header =FALSE,sep=",")
str(data)
'data.frame':	6 obs. of  3 variables:
 $ V1: Factor w/ 6 levels "1000","bird",..: 6 5 3 4 2 1
 $ V2: Factor w/ 3 levels "dog","moon","plane": 2 2 1 2 3 1
 $ V3: Factor w/ 5 levels "2000","catdog",..: 3 4 2 4 5 1
as.numeric(data$V1)
[1] 6 5 3 4 2 1
as.numeric(data$V2)
[1] 2 2 1 2 3 1
as.factor(data$V1)
[1] sun   stars cat   dog   bird  1000 
Levels: 1000 bird cat dog stars sun
as.factor(data$V2)
[1] moon  moon  dog   moon  plane dog  
Levels: dog moon plane

So notice "dog" is 4 in V1, yet its 1 in V2.  Is there a way, either on import, or after, to have factors computed for both columns and assigned
the same internal values?

Brian
To clarify on my previous post, here is a representation of what I am trying to accomplish:

I would like every unique value in either column to be assigned a number so like so:

    V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000

Level			Value
sun			->	0
stars		->	1
cat			->	2
dog			->	3
bird			->	4
1000		->	5
moon		->	6
plane		->	7
catdog		->	8
superman	->	9
2000		->   10
etc
etc

so internally its represented as:

    V1    V2       V3
1   0		6	1
2   1		6	0
3   2		3	8
4   3		6	0
5   4		7	9
6   5		3	10

does this make sense?  I am hoping there is a way to accomplish this.

Brian

I am trying to make it so two columns with similar data use the same internal numbers for same factors, here is the example:

read.csv("test.csv",header =FALSE,sep=",")
    V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000
data <- read.csv("test.csv",header =FALSE,sep=",")
str(data)
'data.frame':	6 obs. of  3 variables:
$ V1: Factor w/ 6 levels "1000","bird",..: 6 5 3 4 2 1
$ V2: Factor w/ 3 levels "dog","moon","plane": 2 2 1 2 3 1
$ V3: Factor w/ 5 levels "2000","catdog",..: 3 4 2 4 5 1

as.numeric(data$V1)
[1] 6 5 3 4 2 1
as.numeric(data$V2)
[1] 2 2 1 2 3 1
as.factor(data$V1)
[1] sun   stars cat   dog   bird  1000 
Levels: 1000 bird cat dog stars sun
as.factor(data$V2)
[1] moon  moon  dog   moon  plane dog  
Levels: dog moon plane

So notice "dog" is 4 in V1, yet its 1 in V2.  Is there a way, either on import, or after, to have factors computed for both columns and assigned
the same internal values?

Brian

Hello,

You can do what you want, but the coding of factors starts at 1 not at 0.

dat <- read.table(text="
V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000
", header = TRUE)

levs <- unique(unlist(dat))

dat$V1 <- factor(dat$V1, levels = levs)
dat$V2 <- factor(dat$V2, levels = levs)
dat$V3 <- factor(dat$V3, levels = levs)

str(dat)
'data.frame':   6 obs. of  3 variables:
  $ V1: Factor w/ 11 levels "sun","stars",..: 1 2 3 4 5 6
  $ V2: Factor w/ 11 levels "sun","stars",..: 7 7 4 7 8 4
  $ V3: Factor w/ 11 levels "sun","stars",..: 2 1 9 1 10 11

Hope this helps,

Rui Barradas
Em 24-11-2012 07:33, Brian Feeny escreveu:
To clarify on my previous post, here is a representation of what I am trying to accomplish:

I would like every unique value in either column to be assigned a number so like so:

     V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000

Level			Value
sun			->	0
stars		->	1
cat			->	2
dog			->	3
bird			->	4
1000		->	5
moon		->	6
plane		->	7
catdog		->	8
superman	->	9
2000		->   10
etc
etc

so internally its represented as:

     V1    V2       V3
1   0		6	1
2   1		6	0
3   2		3	8
4   3		6	0
5   4		7	9
6   5		3	10

does this make sense?  I am hoping there is a way to accomplish this.

Brian

On Nov 23, 2012, at 11:42 PM, Brian Feeny <bfeeny at mac.com> wrote:

I am trying to make it so two columns with similar data use the same internal numbers for same factors, here is the example:

read.csv("test.csv",header =FALSE,sep=",")
     V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000
data <- read.csv("test.csv",header =FALSE,sep=",")
str(data)
'data.frame':	6 obs. of  3 variables:
$ V1: Factor w/ 6 levels "1000","bird",..: 6 5 3 4 2 1
$ V2: Factor w/ 3 levels "dog","moon","plane": 2 2 1 2 3 1
$ V3: Factor w/ 5 levels "2000","catdog",..: 3 4 2 4 5 1

as.numeric(data$V1)
[1] 6 5 3 4 2 1
as.numeric(data$V2)
[1] 2 2 1 2 3 1
as.factor(data$V1)
[1] sun   stars cat   dog   bird  1000
Levels: 1000 bird cat dog stars sun
as.factor(data$V2)
[1] moon  moon  dog   moon  plane dog
Levels: dog moon plane

So notice "dog" is 4 in V1, yet its 1 in V2.  Is there a way, either on import, or after, to have factors computed for both columns and assigned
the same internal values?

Brian

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R-help at r-project.org 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.
Hello,

If you want the factor sorted, you'll have to do it manually.

levs <- sort(unique(as.character(unlist(dat))))

Rui Barradas
Em 24-11-2012 12:57, Rui Barradas escreveu:
Hello,

You can do what you want, but the coding of factors starts at 1 not at 0.

dat <- read.table(text="
V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000
", header = TRUE)

levs <- unique(unlist(dat))

dat$V1 <- factor(dat$V1, levels = levs)
dat$V2 <- factor(dat$V2, levels = levs)
dat$V3 <- factor(dat$V3, levels = levs)

str(dat)
'data.frame':   6 obs. of  3 variables:
 $ V1: Factor w/ 11 levels "sun","stars",..: 1 2 3 4 5 6
 $ V2: Factor w/ 11 levels "sun","stars",..: 7 7 4 7 8 4
 $ V3: Factor w/ 11 levels "sun","stars",..: 2 1 9 1 10 11

Hope this helps,

Rui Barradas
Em 24-11-2012 07:33, Brian Feeny escreveu:
To clarify on my previous post, here is a representation of what I am 
trying to accomplish:

I would like every unique value in either column to be assigned a 
number so like so:

     V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000

Level            Value
sun            ->    0
stars        ->    1
cat            ->    2
dog            ->    3
bird            ->    4
1000        ->    5
moon        ->    6
plane        ->    7
catdog        ->    8
superman    ->    9
2000        ->   10
etc
etc

so internally its represented as:

     V1    V2       V3
1   0        6    1
2   1        6    0
3   2        3    8
4   3        6    0
5   4        7    9
6   5        3    10

does this make sense?  I am hoping there is a way to accomplish this.

Brian

On Nov 23, 2012, at 11:42 PM, Brian Feeny <bfeeny at mac.com> wrote:

I am trying to make it so two columns with similar data use the same 
internal numbers for same factors, here is the example:

read.csv("test.csv",header =FALSE,sep=",")
     V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000
data <- read.csv("test.csv",header =FALSE,sep=",")
str(data)
'data.frame':    6 obs. of  3 variables:
$ V1: Factor w/ 6 levels "1000","bird",..: 6 5 3 4 2 1
$ V2: Factor w/ 3 levels "dog","moon","plane": 2 2 1 2 3 1
$ V3: Factor w/ 5 levels "2000","catdog",..: 3 4 2 4 5 1

as.numeric(data$V1)
[1] 6 5 3 4 2 1
as.numeric(data$V2)
[1] 2 2 1 2 3 1
as.factor(data$V1)
[1] sun   stars cat   dog   bird  1000
Levels: 1000 bird cat dog stars sun
as.factor(data$V2)
[1] moon  moon  dog   moon  plane dog
Levels: dog moon plane

So notice "dog" is 4 in V1, yet its 1 in V2.  Is there a way, either 
on import, or after, to have factors computed for both columns and 
assigned
the same internal values?

Brian

______________________________________________
R-help at r-project.org 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.

I am trying to make it so two columns with similar data use the same  
internal numbers for same factors, here is the example:

read.csv("test.csv",header =FALSE,sep=",")
    V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000
data <- read.csv("test.csv",header =FALSE,sep=",")
str(data)
'data.frame':	6 obs. of  3 variables:
$ V1: Factor w/ 6 levels "1000","bird",..: 6 5 3 4 2 1
$ V2: Factor w/ 3 levels "dog","moon","plane": 2 2 1 2 3 1
$ V3: Factor w/ 5 levels "2000","catdog",..: 3 4 2 4 5 1

as.numeric(data$V1)
[1] 6 5 3 4 2 1
as.numeric(data$V2)
[1] 2 2 1 2 3 1
as.factor(data$V1)
[1] sun   stars cat   dog   bird  1000
Levels: 1000 bird cat dog stars sun
as.factor(data$V2)
[1] moon  moon  dog   moon  plane dog
Levels: dog moon plane

So notice "dog" is 4 in V1, yet its 1 in V2.  Is there a way, either  
on import, or after, to have factors computed for both columns and  
assigned
the same internal values?
> dat[] <- lapply(dat, function(x) factor(as.character(x),
                                           levels=  
levels(unlist(dat)) ) )
 > dat
      V1    V2       V3
1   sun  moon    stars
2 stars  moon      sun
3   cat   dog   catdog
4   dog  moon      sun
5  bird plane superman
6  1000   dog     2000
 > levels(dat[[1]])
  [1] "1000"     "bird"     "cat"      "dog"      "stars"    "sun"
  [7] "moon"     "plane"    "2000"     "catdog"   "superman"

I see your "clarification". Reordering the representation can be done  
with :

levels(dat) <- <character vector>
David Winsemius, MD
Alameda, CA, USA