filling a vector with a tapply function applied to another vector

I have a data frame with three columns. The first one is filled with factors,
the second one with numeric values and the third one is an empty vector.
I need fill the third column with the results of the function
tapply(secondcolumn,firstcolumn,mean) so that I have for each row of the
third column the mean of the second column conditional to the factor element
in the first column.
Thank you very much for your help.
Alb
--
View this message in context: http://r.789695.n4.nabble.com/filling-a-vector-with-a-tapply-function-applied-to-another-vector-tp3039271p3039271.html
Sent from the R help mailing list archive at Nabble.com.

albechan <alberto.casetta at satt.biz> 
Odeslal: r-help-bounces at r-project.org

12.11.2010 10:49

Re: [R] filling a vector with a tapply function applied to another 

The first column has 331 rows, the number of factors in the second 

20 repeated in order to have 331 rows too. What I need is to reapeat in 

third column each of the 20 results derived from
tapply(firstcolumn,secondcolumn,mean) as many times as each factor 

in the second column. So I'll have 331 values in the third column as 

I hope it's clear enough what I need to do.

-- 
View this message in context: 

with-a-tapply-function-applied-to-another-vector-tp3039271p3039337.html
Sent from the R help mailing list archive at Nabble.com.