I would like to have a loop over a list of data frames that converts specific columns from data frames as numeric(in my case its's second and third column of each data frame within the list) I already have some code here and don't know why it isn't working...
Could some1 help me ?
lapply(myfiles2[[]][[,c(2,3)]], as.numeric)
This is not so hard. Yoy have to loop (lapply) through the list changing each member data.frame's columns of interest with another call to lapply.
First, some example dataset, since you have posted none.
set.seed(1234)
myfiles2 <- lapply(1:4, function(i){
data.frame(X = letters[1:5], Y = factor(sample(5)), Z = as.character(11:15))
})
str(myfiles2) # output omited
Now, the problem.
cols <- 2:3
myfiles3 <- lapply(myfiles2, function(DF){
DF[cols] <- lapply(DF[cols], as.numeric)
DF
})
To see that it worked any of the following two will do.
lapply(myfiles3, function(DF) sapply(DF, class))
str(myfiles3)
#List of 4
# $ :'data.frame': 5 obs. of 3 variables:
# ..$ X: Factor w/ 5 levels "a","b","c","d",..: 1 2 3 4 5
# ..$ Y: num [1:5] 1 3 2 4 5
# ..$ Z: num [1:5] 1 2 3 4 5
# $ :'data.frame': 5 obs. of 3 variables:
# ..$ X: Factor w/ 5 levels "a","b","c","d",..: 1 2 3 4 5
# ..$ Y: num [1:5] 4 1 5 2 3
# ..$ Z: num [1:5] 1 2 3 4 5
# $ :'data.frame': 5 obs. of 3 variables:
# ..$ X: Factor w/ 5 levels "a","b","c","d",..: 1 2 3 4 5
# ..$ Y: num [1:5] 4 3 1 2 5
# ..$ Z: num [1:5] 1 2 3 4 5
# $ :'data.frame': 5 obs. of 3 variables:
# ..$ X: Factor w/ 5 levels "a","b","c","d",..: 1 2 3 4 5
# ..$ Y: num [1:5] 5 2 1 3 4
# ..$ Z: num [1:5] 1 2 3 4 5
