writing a function to calculate the mean of columns in a dataframe in R

Question

I have to calculate the mean of the columns in a dataframe by writing a function and then applying it. I understand that this is easy to do with mean and

Answer 1

Here's an example by slightly modifying your second attempt

mean_fun<-function(x){
    mean_c = numeric(0)
    for( i in 1:ncol(x)){
        s = sum(x[,i], na.rm=TRUE)
        l = length(x[,i][is.na(x[,i]) == FALSE])
        mean_c[i] = s/l
    }
    return (mean_c)
}

USAGE

mean_fun(mtcars)
# [1]  20.090625   6.187500 230.721875 146.687500   3.596563   3.217250  17.848750   0.437500   0.406250
#[10]   3.687500   2.812500