R help - Mar 2010 - format: from list to data frame

Dear users,

Is anyone out there on a Saturday to answer this easy question?

I have the "yo" object data in a "list" format:
> str(yo)
 num [1:259, 1:173] 16.3 NA NA NA NA ...
 - attr(*, "dimnames")=List of 2
  ..$ x: chr [1:259] "367319" "367329" "367309"
"367339" ...
  ..$ y: chr [1:173] "780175" "780185" "780195"
"780205" ...
> length(yo)
[1] 44807

where x is the name of the rows and y the name of the columns (coordinates)
of a matrix of 44807 values

how can I get a data.frame with these three columns: x, y, values

Many thanks to the Saturday working people.

Javier					








and I want to produce a data frame

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On Mar 13, 2010, at 11:46 AM, Javier wrote:
>
> Dear users,
>
> Is anyone out there on a Saturday to answer this easy question?
>
> I have the "yo" object data in a "list" format:
>
>> str(yo)
> num [1:259, 1:173] 16.3 NA NA NA NA ...
> - attr(*, "dimnames")=List of 2
>  ..$ x: chr [1:259] "367319" "367329"
"367309" "367339" ...
>  ..$ y: chr [1:173] "780175" "780185"
"780195" "780205" ...
>> length(yo)
> [1] 44807
>
> where x is the name of the rows and y the name of the columns  
> (coordinates)
> of a matrix of 44807 values
>
> how can I get a data.frame with these three columns: x, y, values
?as.data.frame.table

 > as.data.frame.table(matrix((1:16)/16, ncol=2))
    Var1 Var2   Freq
1     A    A 0.0625
2     B    A 0.1250
3     C    A 0.1875
4     D    A 0.2500
5     E    A 0.3125
6     F    A 0.3750
7     G    A 0.4375
8     H    A 0.5000
9     A    B 0.5625
10    B    B 0.6250
11    C    B 0.6875
12    D    B 0.7500
13    E    B 0.8125
14    F    B 0.8750
15    G    B 0.9375
16    H    B 1.0000


You will need to relabel the columns but the "names()<-" function
will
suffice.

--
David.
>
> Many thanks to the Saturday working people.
>
> Javier					
>
>
>
>
>
>
>
>
> and I want to produce a data frame
>
> -- 
> View this message in context:
http://n4.nabble.com/format-from-list-to-data-frame-tp1591773p1591773.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> 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.
David Winsemius, MD
West Hartford, CT

On Sat, Mar 13, 2010 at 4:46 PM, Javier <j.perez-barberia at
macaulay.ac.uk> wrote:
>
> Dear users,
>
> Is anyone out there on a Saturday to answer this easy question?
>
> I have the "yo" object data in a "list" format:
>
>> str(yo)
> ?num [1:259, 1:173] 16.3 NA NA NA NA ...
> ?- attr(*, "dimnames")=List of 2
> ?..$ x: chr [1:259] "367319" "367329"
"367309" "367339" ...
> ?..$ y: chr [1:173] "780175" "780185"
"780195" "780205" ...
>> length(yo)
> [1] 44807
>
> where x is the name of the rows and y the name of the columns (coordinates)
> of a matrix of 44807 values
>
> how can I get a data.frame with these three columns: x, y, values
>
> Many thanks to the Saturday working people.
 Let's try with something a bit smaller. Not sure what you mean by
list format, your thing looks like a matrix:

d=matrix(1:12,ncol=4)
dimnames(d) <- list(letters[1:3],letters[9:12])

- hence:

 > str(d)
 int [1:3, 1:4] 1 2 3 4 5 6 7 8 9 10 ...
 - attr(*, "dimnames")=List of 2
  ..$ : chr [1:3] "a" "b" "c"
  ..$ : chr [1:4] "i" "j" "k" "l"
 > length(d)
 [1] 12

If I use 'melt' from the 'reshape' package:
> require(reshape)
> melt(d)
   X1 X2 value
1   a  i     1
2   b  i     2
3   c  i     3
4   a  j     4
5   b  j     5
6   c  j     6
7   a  k     7
8   b  k     8
9   c  k     9
10  a  l    10
11  b  l    11
12  c  l    12

I think I get pretty much what you want. You might need to set the
columns to numeric and maybe change the names.

Barry

On Mar 13, 2010, at 10:46 AM, Javier wrote:
> 
> Dear users,
> 
> Is anyone out there on a Saturday to answer this easy question?
> 
> I have the "yo" object data in a "list" format:

It is not a list, it is a matrix.  The dimnames attribute is a list.

>> str(yo)
> num [1:259, 1:173] 16.3 NA NA NA NA ...
> - attr(*, "dimnames")=List of 2
>  ..$ x: chr [1:259] "367319" "367329"
"367309" "367339" ...
>  ..$ y: chr [1:173] "780175" "780185"
"780195" "780205" ...
>> length(yo)
> [1] 44807
> 
> where x is the name of the rows and y the name of the columns (coordinates)
> of a matrix of 44807 values
> 
> how can I get a data.frame with these three columns: x, y, values
> 
> Many thanks to the Saturday working people.
> 
> Javier					
Try:

 as.data.frame.table(yo)

HTH,

Marc Schwartz