ibombonato

library(lubridate)

mother2 <- as.data.frame(list(month=c(2,2), day=c(28,30), year=c(1988, 1988)))

mother2$birth1 <- mapply(function(y, m, d){
  my_data <- paste0(as.character(y), 
                 "-", as.character(m), 
                 "-", as.character(d))
  ifelse(is.na(lubridate::ymd(my_data, quiet = TRUE)), NA, as.POSIXct(my_data, origin="1970-01-01"))
}, y = mother2$year, m = mother2$month, d = mother2$day)

ibombonato

library(doParallel)
library(foreach)

my_data <- mtcars

# Within Sum of Squares
wss <- (nrow(my_data)-1)*sum(apply(my_data,2,var))

# Number of clusters
try_clusters <- seq(from = 2, to = 8, by = 1)