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Using Function

2 messages · Silvano, PIKAL Petr

Original
Silvano
# 
Hi,

I have some simple statistics to calculate for a large 
number of variables.
I created a simple function to apply to variables.
I would like the variable name to be placed automatically.
I tried the following function but is not working.

desc = function(x){
                 media = mean(x, na.rm=T)
                 desvio = sd(x, na.rm=T)
                 cv = desvio/media*100
                 saida = cbind(media, desvio, cv)
                 colnames(saida) = c(NULL, 'M?dia', 
'Desvio', 'CV')
                 rownames(saida) = c(x)
                 saida
 }

desc(Idade)

         M?dia  Desvio      CV
Idade 44.04961 16.9388 38.4539

How do you get the variable name is placed as the first 
element?

My objective is get something like:

rbind(
desc(Altura),
desc(Idade),
desc(IMC),
desc(FC),
desc(CIRCABD),
desc(GLICOSE),
desc(UREIA),
desc(CREATINA),
desc(CTOTAL),
desc(CHDL),
desc(CLDL),
desc(CVLDL),
desc(TRIG),
desc(URICO),
desc(SAQRS),
desc(SOKOLOW_LYON),
desc(CORNELL),
desc(QRS_dur),
desc(Interv_QT)
)

Thanks a lot,

--------------------------------------
Silvano Cesar da Costa
Departamento de Estat?stica
Universidade Estadual de Londrina
Fone: 3371-4346
PIKAL Petr
# 
Hi
You are quite close. This seems to do what you want if I presume that your 
variables are located in data frame

desc = function(x){
                 media = mean(x, na.rm=T)
                 desvio = sd(x, na.rm=T)
                 cv = desvio/media*100
                 saida = data.frame(Media=media, Desvio=desvio, CV=cv)
                 saida
 }

iris4 <- iris[,1:4]

sapply(iris4, desc)
       Sepal.Length Sepal.Width Petal.Length Petal.Width
Media  5.843333     3.057333    3.758        1.199333 
Desvio 0.8280661    0.4358663   1.765298     0.7622377 
CV     14.17113     14.25642    46.97441     63.55511 

If you want switch rows and cols use 

t(sapply(iris4, desc))

Regards
Petr
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