Using gsub in R to for conditional matching with multiple patterns

Question

I'm trying to reformat a dynamic string that describes the day's date. Today's string is "December 6, 2020". Tomorrow it will be "December 7, 2020".

I'd like to reformat the string so that days of the month 1-9 are written "01", "02", etc.

The string is scraped, but for illustrative purposes let's just say:

lastupDate <- "December 6, 2020"

Below is a very clunky, repetitive way to reformat the string no matter the actual date:

lastupDATE <- gsub(" 1,", " 01,", lastupDATE)
lastupDATE <- gsub(" 2,", " 02,", lastupDATE)
lastupDATE <- gsub(" 3,", " 03,", lastupDATE)
lastupDATE <- gsub(" 4,", " 04,", lastupDATE)
lastupDATE <- gsub(" 5,", " 05,", lastupDATE)
lastupDATE <- gsub(" 6,", " 06,", lastupDATE)
lastupDATE <- gsub(" 7,", " 07,", lastupDATE)
lastupDATE <- gsub(" 8,", " 08,", lastupDATE)
lastupDATE <- gsub(" 9,", " 09,", lastupDATE)

This is pretty ugly. It does the trick, but I'm curious if anyone has a better idea.

Many thanks!

Answer 1

We can convert to Date class and then do the format

format(as.Date(lastupDate, '%B %d, %Y'), "%m %d, %Y")
#[1] "12 06, 2020"