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Median

4 messages · Jose Sierra, José Fernández Menéndez, R. Villegas +1 more

#
Hello.

I need calculate the median of several column of a data.frame, in a new 
column of this data frame, but the median operator only calculate from a 
vector.

I have made a functionc that calculate the median but it is very slow. 
Are there any method in any package to calculate this?

Best regards.
Jose Sierra.

           A                        B                        C
-0.01678042      -0.0003354948     -0.0003354948
 0.17320485       0.2359448911      0.4884204711
-0.76066019      -0.6024409891     -0.5814788340
-0.04365426      -0.0060560612     -0.0025470274
 0.01885735       0.0027792718      0.0184081858
-0.07275884      -0.0371542622     -0.0315041630
  0.05740122       0.0814235514      0.0468193512
 -0.05404834      -0.0590145580      0.0489612929
 -0.28197518      -0.1899247807     -0.2089076920
 -0.02465713      -0.2222512947     -0.2688619668
#
i don't understand very well but
apply(your_data_frame, 1,median) calculates the median of every row of
your data frame
apply(your_data_frame, 2, median) calculates the median  of every column

2007/5/8, Jose Sierra <jose.sierra at integromics.com>:
#
2007/5/8, Jose Sierra <jose.sierra at integromics.com>:
Maybe you can start with this:

m2 <- data.frame(matrix(c(
-0.01678042,      -0.0003354948,     -0.0003354948,
 0.17320485,       0.2359448911,      0.4884204711,
-0.76066019,      -0.6024409891,     -0.5814788340,
-0.04365426,      -0.0060560612,     -0.0025470274,
 0.01885735,       0.0027792718,      0.0184081858,
-0.07275884,      -0.0371542622,     -0.0315041630,
 0.05740122,       0.0814235514,      0.0468193512,
-0.05404834,      -0.0590145580,      0.0489612929,
-0.28197518,      -0.1899247807,     -0.2089076920,
-0.02465713,      -0.2222512947,     -0.2688619668
),nrow=10))

m2[,4]<- median(m2[,1])
m2[,5]<- median(m2[,2])
m2[,6]<- median(m2[,3])

Rod.
#
Please, Jose,  do NOT misuse  R-devel for such questions!

There's R-help (and many good books on R and maybe your local R expert)
for asking such questions.

Definitely *not* the R-devel mailing list.

--> http://www.R-project.org/mail.html , the posting guide, etc.

Martin Maechler, ETH Zurich
{as maintainer of these R mailing lists}
............