Capítulo 17 Condicionais e loops

# -----------------------------------------------------------------------------
# Loop for:
# -----------------------------------------------------------------------------

vari = 0
for(i in 1:5){
      vari[i] = i
}
vari
## [1] 1 2 3 4 5
vv = list()
for(i in 1:5){
      vv[[i]] = i
}
vv
## [[1]]
## [1] 1
## 
## [[2]]
## [1] 2
## 
## [[3]]
## [1] 3
## 
## [[4]]
## [1] 4
## 
## [[5]]
## [1] 5
meudados = data.frame(v1=rnorm(100),
                      v2=rnorm(100),
                      v3=rnorm(100),
                      v4=rnorm(100))
medias = NULL

#De um modo restrito
for(i in 1:4){
  
  medias[i] = mean(meudados[,i])
  names(medias)[i] = names(meudados)[i]

}

#De um modo mais amplo, generalizado
for(i in 1:ncol(meudados)){

  medias[i] = mean(meudados[,i])
  names(medias)[i] = names(meudados)[i]

}
medias
##          v1          v2          v3          v4 
##  0.07570056 -0.03693063 -0.09143181 -0.12431440
# -----------------------------------------------------------------------------
# Loop while:
# -----------------------------------------------------------------------------
z = 0
while(z < 5) {
  z = z + 2
  print(z)
}
## [1] 2
## [1] 4
## [1] 6
# -----------------------------------------------------------------------------
# Loop repeat:
# -----------------------------------------------------------------------------
z = 0
repeat{
  z = z + 2
  print(z)
  if(z > 4){
    break()
  }
}     
## [1] 2
## [1] 4
## [1] 6