[R] Counting Frequencies in Data Frame

[William Dunlap]

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of M.Ribeiro
> Sent: Tuesday, May 18, 2010 7:13 AM
> To: r-help at r-project.org
> Subject: [R] Counting Frequencies in Data Frame
> 
> 
> Hi,
> I am sure there is an easy way to do it, but I can't find it.
> I have a data frame that has 15 columns and 7000 rows.
> 
> The only values inside the data.frame are "aa", "ab", "bb" as 
> you can see an
> example bellow.
> 
>    1  2  3
> 1 aa ab ab
> 2 ab ab ab
> 3 aa aa aa
> 4 bb bb bb
> 
> What I would like to do, is to generate a vector (or another 
> data.frame)
> with 7000 rows, and 3 columns. In the first column, the 
> information about
> how many aa, the second about how many ab, and the third 
> about how many bb
> are there in each line
>   aa  ab  bb
> 1  1   2   0
> 2  0   2   0
    -->  3?  <--
> 3  3   0   0
> 4  0   0   3

You could make a "table" (a sort of "matrix") of the
data entries and their row numbers:
  
  > tmp <- read.table(header=TRUE, check.names=FALSE, textConnection("
  +    1  2  3
  + 1 aa ab ab
  + 2 ab ab ab
  + 3 aa aa aa
  + 4 bb bb bb
  + "))
  > table(row(tmp), as.matrix(tmp))
     
      aa ab bb
    1  1  2  0
    2  0  3  0
    3  3  0  0
    4  0  0  3

The as.matrix() is needed to force all the columns of the
data.frame into one vector.

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com 
> 
> Thank you very much
> Cheers
> -- 
> View this message in context: 
> http://r.789695.n4.nabble.com/Counting-Frequencies-in-Data-Fra
me-tp2221342p2221342.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.
>