Formatting a date in R without leading zeros

Question

Is there a way to use the format function on a date object, specifically an object of class POSIXlt, POSIXct, or Date, with the format %Y, %m, %d such that leading zeros are stripped from each of those 3 fields?

For example, I would like format(as.Date("1998-09-02"), "%Y, %m, %d") to return 1998, 9, 2 and not 1998, 09, 02.

Answer 1

Just remove the leading zeros at the end:

gsub(" 0", " ", format(as.Date("1998-09-02"), "%Y, %m, %d")) ## [1] "1998, 9, 2" 

Use %e to obtain a leading space instead of a leading zero.

Answer 2

You can do this with a simple change to your strftime format string. However, it depends on your platform (Unix or Windows).

Unix

Insert a minus sign (-) before each term you'd like to remove leading zeros from:

format(as.Date("2020-06-02"), "%Y, %-m, %-d") [1] "2020, 6, 2" 

Windows

Insert a pound sign (#) before each desired term:

format(as.Date("2020-06-02"), "%Y, %#m, %#d") [1] "2020, 6, 2"