[R] working with pairlists imported from HDF5, converting to data frames?

From: Paul Johnson <pauljohn_at_ku.edu>
Date: Thu 17 Mar 2005 - 06:52:36 EST


I've used the HDF5 library to bring some data into R. THe verbose output looks like this:

>

hdf5load("hdfGraphWed_Mar_16_13_33_37_2005.hdf",load=T,verbosity=1,tidy=T)

Processing object: cprSeats ...... which is a Group
Processing object: Seats 0 ...... its a dataset......Finished dataset
Processing object: Seats 1 ...... its a dataset......Finished dataset
Processing object: Seats 2 ...... its a dataset......Finished dataset
Processing object: Seats 3 ...... its a dataset......Finished dataset
Processing object: Seats 4 ...... its a dataset......Finished dataset
... Done group cprSeats
Processing object: effective ...... which is a Group
Processing object: AggComp ...... its a dataset......Finished dataset
Processing object: AggNonComp ...... its a dataset......Finished dataset
Processing object: CPR ...... its a dataset......Finished dataset
Processing object: PR ...... its a dataset......Finished dataset
Processing object: SMD ...... its a dataset......Finished dataset
... Done group effective

Each item inside the group "effective" is a vector of numbers. I want to convert effective into a data frame or matrix for use with matplot.

However, R sees effective not as a collection of vectors, but as a pairlist. I'm not a Lisp programmer, so don't understand the significance of the list help page's comment about dotted lists.

> class(effective)

[1] "pairlist"
> attributes(effective)

$names
[1] "SMD" "PR" "CPR" "AggNonComp" "AggComp"

I can access the elements in effective as list elements, either with effective$SMD or effective[[1]], as in:

> effective[[1]]

   [1] 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000

   [9] 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000
  [17] 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000
  [25] 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000 4.761905 4.668534
  [33] 4.743833 4.743833 4.694836 4.672897 4.612546 4.612546 4.612546 4.950495
  [41] 4.766444 4.761905 4.329004 4.990020 4.930966 4.906771 4.378284 4.686036
  [49] 4.935834 4.793864 4.793864 4.541326 4.849661 4.730369 4.960317 4.159734

But I can't force it into a data frame

> as.data.frame(effective)

Error in as.data.frame.default(effective) :

         can't coerce pairlist into a data.frame

But I can manually build the dataframe

>

data.frame(effective$SMD,effective$PR,effective$CPR,effective$AggNonComp,effective$AggComp)

But that is a bit frustrating for every individual dataset coming in.

Is there a short cut?

-- 
Paul E. Johnson                       email: pauljohn@ku.edu
Dept. of Political Science            http://lark.cc.ku.edu/~pauljohn
1541 Lilac Lane, Rm 504
University of Kansas                  Office: (785) 864-9086
Lawrence, Kansas 66044-3177           FAX: (785) 864-5700

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Received on Thu Mar 17 06:57:08 2005

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