你可以试试，

format(strptime(substr(as.POSIXct(sprintf("%04.0f", x), 
                                 format="%H%M"), 12, 16), '%H:%M'), '%I:%M %p')

#[1] "08:14 AM" "08:30 AM" "06:35 PM" "05:30 PM" "02:42 PM" "08:20 AM"

数据

x <- c(814, 830, 1835, 1730,1442, 820)