R help - Apr 2011 - Unlist command drops all my column names in the first row and adopts NAs

Hi Everyone, 

I am having trouble turning my data.frame into a matrix format. Because I
wanted to change my data.frame with mostly factor variables into a numeric
matrix, I used the following code -->
UN2010frame<-data.matrix(lapply(UN2010,as.numeric))

However when i checked the mode of the UN2010frame, it still showed up as a
list. Because the code I want to run (Ordrating) does not accept data in a
list format, I used UN2010matrix <- unlist(UN2010frame) to unlist my matrix.
When I did this, my first row ( which was formerly a row with column names)
turned into NAs. This was a problem for me because when I tried to run an
ordinal IRT model using this data set, I got the following error message. 

Error in 1:nrow(Y) : argument of length 0

I think it is because all the values in my first row are now gone.... 

If you could help me on any front, It would be deeply appreciated. Thank you
very much!

Haillie 


--
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Why not just data.matrix(UN2010) ?

--- On Wed, 4/20/11, Haillie <nal at princeton.edu> wrote:
> From: Haillie <nal at princeton.edu>
> Subject: [R] Unlist command drops all my column names in the first row and
adopts NAs
> To: r-help at r-project.org
> Received: Wednesday, April 20, 2011, 11:05 AM
> Hi Everyone, 
> 
> I am having trouble turning my data.frame into a matrix
> format. Because I
> wanted to change my data.frame with mostly factor variables
> into a numeric
> matrix, I used the following code -->
> UN2010frame<-data.matrix(lapply(UN2010,as.numeric))
> 
> However when i checked the mode of the UN2010frame, it
> still showed up as a
> list. Because the code I want to run (Ordrating) does not
> accept data in a
> list format, I used UN2010matrix <- unlist(UN2010frame)
> to unlist my matrix.
> When I did this, my first row ( which was formerly a row
> with column names)
> turned into NAs. This was a problem for me because when I
> tried to run an
> ordinal IRT model using this data set, I got the following
> error message. 
> 
> Error in 1:nrow(Y) : argument of length 0
> 
> I think it is because all the values in my first row are
> now gone.... 
> 
> If you could help me on any front, It would be deeply
> appreciated. Thank you
> very much!
> 
> Haillie 
> 
> 
> --
> View this message in context:
http://r.789695.n4.nabble.com/Unlist-command-drops-all-my-column-names-in-the-first-row-and-adopts-NAs-tp3463294p3463294.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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