Convert numbers to HH:MM in R

I’m working with a dataset with a time column in the following format:

Time 
330 
2230 
5 
45 

I want to convert this to hh:mm format

Time 
03:30 
22:30 
00:05 
00:45 

I’m new to R and I’m wondering if there’s an easy way to do this.
Any help would be appreciated.

>Solution :

You can pad the time strings to 4-digit with "0" on the left, then split the padded strins into HH:MM.

df <- data.frame(Time = c(330, 2230, 5, 45))

# solution 1
df$Time2 <- sub("(.{2})(.+)", "\\1:\\2", sprintf("%04d", df$Time))

# solution 2
df$Time2 <- format(strptime(sprintf("%04d", df$Time), "%H%M"), "%H:%M")

df
#   Time Time2
# 1  330 03:30
# 2 2230 22:30
# 3    5 00:05
# 4   45 00:45