R help - Jul 2003 - Characters and Numeric Values in One Matrix

Dear R-Users,

I want to ask a question for a colleague of mine. He wants to put a
character vector and a numeric vector into one matrix and still have the old
character and numeric type for the respective columns.
Unfortunately, I am just starting using R and I could not help him.
Is there an easy and straightforward way to do this in R?
	
Maybe a little example facilitates understanding our problem:
names <- c("Marge", "Lisa", "Homer",
"Bart", "Maggie")
ages <- c(38,10,41,8,1)
Now he wants to have 2 columns in a matrix which should look like this:
"Marge"     38
"Lisa"      10
"Homer"     41
"Bart"       8
"Maggie"     1

I thought about using either:
family1 <- matrix(c(names, ages), ncol=2, byrow=FALSE)
or
family2 <- data.frame(names,ages)
but this simply transformed either the numeric into character values
(family1) or the character values into factor levels (family2)
Anyone here who can give us some advice on this?

We are using R 1.7.0 on Windows NT.

Thanks,
Roland

Dear Roland,

Matrices can only be made of values of the same type, so you can't them
here.

data.frame is the right track. ?data.frame states:

     Character variables passed to `data.frame' are converted to factor
     columns unless protected by `I'. It also applies to adding columns
     to a data frame.

So, try 
> family2 <- data.frame(I(names),ages)
> family2$names
[1] "Marge"  "Lisa"   "Homer"  "Bart"  
"Maggie"
> is.factor(family2$names)
[1] FALSE

HTH,

Thomas

---

Thomas Hotz
Research Associate in Medical Statistics
University of Leicester
United Kingdom

Department of Epidemiology and Public Health
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Leicester
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Division of Medicine for the Elderly
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Fax +44 116 232-2976

> -----Original Message-----
> From: Rau, Roland [mailto:Rau at demogr.mpg.de]
> Sent: 08 July 2003 10:13
> To: 'r-help at stat.math.ethz.ch'
> Subject: [R] Characters and Numeric Values in One Matrix
> 
> 
> Dear R-Users,
> 
> I want to ask a question for a colleague of mine. He wants to put a
> character vector and a numeric vector into one matrix and 
> still have the old
> character and numeric type for the respective columns.
> Unfortunately, I am just starting using R and I could not help him.
> Is there an easy and straightforward way to do this in R?
> 	
> Maybe a little example facilitates understanding our problem:
> names <- c("Marge", "Lisa", "Homer",
"Bart", "Maggie")
> ages <- c(38,10,41,8,1)
> Now he wants to have 2 columns in a matrix which should look 
> like this:
> "Marge"     38
> "Lisa"      10
> "Homer"     41
> "Bart"       8
> "Maggie"     1
> 
> I thought about using either:
> family1 <- matrix(c(names, ages), ncol=2, byrow=FALSE)
> or
> family2 <- data.frame(names,ages)
> but this simply transformed either the numeric into character values
> (family1) or the character values into factor levels (family2)
> Anyone here who can give us some advice on this?
> 
> We are using R 1.7.0 on Windows NT.
> 
> Thanks,
> Roland
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
>

Hi Roland,

Try the following

 > names <- c("Marge", "Lisa", "Homer",
"Bart", "Maggie")
 > ages <- c(38,10,41,8,1)
 > simpsons <- data.frame(I(names), ages)
 > simpsons
    names ages
1  Marge   38
2   Lisa   10
3  Homer   41
4   Bart    8
5 Maggie    1
 > str(simpsons)
`data.frame':   5 obs. of  2 variables:
  $ names:Class 'AsIs'  chr [1:5] "Marge" "Lisa"
"Homer" "Bart" ...
  $ ages : num  38 10 41 8 1

Note the use of I() to protect names from the implicit conversion from 
character to factor that data.frame() does.

See ?data.frame for more.

HTH

Gav

Rau, Roland wrote:
> Dear R-Users,
> 
> I want to ask a question for a colleague of mine. He wants to put a
> character vector and a numeric vector into one matrix and still have the
old
> character and numeric type for the respective columns.
> Unfortunately, I am just starting using R and I could not help him.
> Is there an easy and straightforward way to do this in R?
> 	
> Maybe a little example facilitates understanding our problem:
> names <- c("Marge", "Lisa", "Homer",
"Bart", "Maggie")
> ages <- c(38,10,41,8,1)
> Now he wants to have 2 columns in a matrix which should look like this:
> "Marge"     38
> "Lisa"      10
> "Homer"     41
> "Bart"       8
> "Maggie"     1
> 
> I thought about using either:
> family1 <- matrix(c(names, ages), ncol=2, byrow=FALSE)
> or
> family2 <- data.frame(names,ages)
> but this simply transformed either the numeric into character values
> (family1) or the character values into factor levels (family2)
> Anyone here who can give us some advice on this?
> 
> We are using R 1.7.0 on Windows NT.
> 
> Thanks,
> Roland
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> 
> 
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Gavin Simpson                     [T] +44 (0)20 7679 5522
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ENSIS Ltd. & ECRC                 [E] gavin.simpson at ucl.ac.uk
UCL Department of Geography       [W] http://www.ucl.ac.uk/~ucfagls/cv/
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Thank you very much for the advice using 
data.frame(I(names), ages)
I received two solutions within 15 minutes of my initial request.
What a quick and nice counterexample for the often heard claim: "Free
Software does not give you any support!"

Thanks again,
Roland