R help - Apr 2005 - Error in hist.default(A) : `x' must be numeric

Dear everybody!
I have load a list A of numbers and want a histogram to be drawn.
on
hist(Y)
the Machine returns:
Error in hist.default(A) : `x' must be numeric
I found out, that the list is of type data.frame.
Y<-as.numeric(Y)
returns
Error in as.double.default(A) : (list) object cannot be coerced to double
What schould I do?
Than you in advance!

Mag. Ferri Leberl wrote:
> Dear everybody!
> I have load a list A of numbers and want a histogram to be drawn.
> on
> hist(Y)
> the Machine returns:
> Error in hist.default(A) : `x' must be numeric
> I found out, that the list is of type data.frame.
> Y<-as.numeric(Y)
> returns
> Error in as.double.default(A) : (list) object cannot be coerced to double
> What schould I do?
> Than you in advance!
Extract the relevant vector from your data frame Y (this is a very 
prbably guess).

Uwe Ligges
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Mag. Ferri Leberl wrote on 4/6/2005 9:57 AM:
> Dear everybody!
> I have load a list A of numbers and want a histogram to be drawn.
> on
> hist(Y)
> the Machine returns:
> Error in hist.default(A) : `x' must be numeric
> I found out, that the list is of type data.frame.
> Y<-as.numeric(Y)
> returns
> Error in as.double.default(A) : (list) object cannot be coerced to double
> What schould I do?
> Than you in advance!
> 
The error messages cannot be more explicit. Y is a list (or data.frame). 
If you're trying to plot a histogram of a component in Y, use the
"[["
or "$" extractors. E.g.

Y <- data.frame(x = rnorm(100))
hist(Y$x)

I would suggest you learn to use ?str if you don't know what Y is.

--sundar

> From: Uwe Ligges
> 
> Mag. Ferri Leberl wrote:
> > Dear everybody!
> > I have load a list A of numbers and want a histogram to be drawn.
> > on
> > hist(Y)
> > the Machine returns:
> > Error in hist.default(A) : `x' must be numeric
> > I found out, that the list is of type data.frame.
> > Y<-as.numeric(Y)
> > returns
> > Error in as.double.default(A) : (list) object cannot be 
> coerced to double
> > What schould I do?
> > Than you in advance!
> 
> Extract the relevant vector from your data frame Y (this is a very 
> prbably guess).
I suspect Ferri might have the numbers in one line in a file, and read them
into R with read.table().  That would put the numbers into a data frame with
n variables and one observation.  If that's the case, just replacing
read.table() with scan() should do it.

Andy

 
> Uwe Ligges
>