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Add column index number to str() output

4 messages · seth.fore, Peter Ehlers, David Winsemius +1 more

seth.fore
# 
I often find it would be very useful when inspecting a data structure using str() to know the column index number in order to rearrange the data in a manner amenable to my purpose. Is there a way to modify the display options of the str() function to add column index? I know this is really a trivial matter but it would increase the utility of the str() function for me and increase the speed with which I can manipulate the data structure. Thanks, 

Seth
Peter Ehlers
#
On 2012-11-23 08:54, seth.fore wrote:
Presumably, you're talking about dataframes. I don't see this
as particularly useful unless you're in the habit of processing
your data by column _number_ rather than variable _name_.
If so, I would strongly discourage that habit.
And a cursory look at str.default() suggests that it may not be
all that trivial a code change.

Peter Ehlers
David Winsemius
#
On Nov 23, 2012, at 12:40 PM, Peter Ehlers wrote:

            

      
      
      
    

        
I would offer the possibility of using names(dfrm) instead of  
str(dfrm) for this purpose. It would be reasonably easy to look at the  
output and figure out numbering. If you wanted every number in a  
single column. then use as.matrix(names(dfrm)).

 > names(apistrat)
  [1] "cds"      "stype"    "name"     "sname"    "snum"     "dname"
  [7] "dnum"     "cname"    "cnum"     "flag"     "pcttest"  "api00"
[13] "api99"    "target"   "growth"   "sch.wide" "comp.imp" "both"
[19] "awards"   "meals"    "ell"      "yr.rnd"   "mobility" "acs.k3"
[25] "acs.46"   "acs.core" "pct.resp" "not.hsg"  "hsg"      "some.col"
[31] "col.grad" "grad.sch" "avg.ed"   "full"     "emer"     "enroll"
[37] "api.stu"  "pw"       "fpc"
 > as.matrix(names(apistrat))
       [,1]
  [1,] "cds"
  [2,] "stype"
  [3,] "name"
  [4,] "sname"
  [5,] "snum"
  [6,] "dname"
  [7,] "dnum"
  [8,] "cname"
  [9,] "cnum"
[10,] "flag"
[11,] "pcttest"
[12,] "api00"
[13,] "api99"
[14,] "target"
[15,] "growth"
[16,] "sch.wide"
[17,] "comp.imp"
[18,] "both"
[19,] "awards"
[20,] "meals"
[21,] "ell"
[22,] "yr.rnd"
[23,] "mobility"
[24,] "acs.k3"
[25,] "acs.46"
[26,] "acs.core"
[27,] "pct.resp"
[28,] "not.hsg"
[29,] "hsg"
[30,] "some.col"
[31,] "col.grad"
[32,] "grad.sch"
[33,] "avg.ed"
[34,] "full"
[35,] "emer"
[36,] "enroll"
[37,] "api.stu"
[38,] "pw"
[39,] "fpc"

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      David L Carlson
    

    

      
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You could create a simple function using this as a starting point:

str.ext <- function(x) {
     if(!is.data.frame(x)) stop("No data frame!")
     st <- gsub(" \\$", "", capture.output(str(x)))
     nm <- prettyNum(0:length(x), width=3)
     cat("\n", paste(nm, st, "\n", sep=" "))
}
str.ext(iris)

   0 'data.frame':      150 obs. of  5 variables: 
   1  Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ... 
   2  Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ... 
   3  Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ... 
   4  Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ... 
   5  Species     : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1
1 1 1 1 ... 

----------------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77843-4352