How to extract numeric values from a structure object in R

Claudio Meo picture Claudio Meo · Sep 24, 2012 · Viewed 7.4k times · Source

I need to extract numeric values from a variable which is a structure combined with numeric values and names

structure(c(-1.14332132657709, -1.1433213265771, -1.20580568266868, 
-1.75735158849487, -1.35614113300058), .Names = c("carbon", 
"nanotubes", "potential", "neuron", "cell", "adhesion"))

At the end I would like to have a vector with just this information

c(-1.14332132657709, -1.1433213265771, -1.20580568266868, 
-1.75735158849487, -1.35614113300058)

how can I do it? many thanks

Answer

Dirk Eddelbuettel picture Dirk Eddelbuettel · Sep 24, 2012

Both as.numeric() and unname() do this:

R> structure(c(-1.14332132657709, -1.1433213265771, -1.20580568266868,
+              -1.75735158849487, -1.35614113300058, NA),
+            .Names = c("carbon", "nanotubes", "potential", 
+            "neuron", "cell", "adhesion"))
   carbon nanotubes potential    neuron      cell  adhesion 
 -1.14332  -1.14332  -1.20581  -1.75735  -1.35614        NA 
R> foo
   carbon nanotubes potential    neuron      cell  adhesion 
 -1.14332  -1.14332  -1.20581  -1.75735  -1.35614        NA 
R>
R> as.numeric(foo)            ## still my 'default' approach
[1] -1.14332 -1.14332 -1.20581 -1.75735 -1.35614       NA
R>
R> unname(foo)                ## maybe preferable though
[1] -1.14332 -1.14332 -1.20581 -1.75735 -1.35614       NA
R>