r - POSIXlt 12-hour time with-out leading zeros -

i attempting eliminate leading 0 of 12-hour time value, graphing purposes result must posixlt value. therefore, can-not use regular expressions because leave result character instead of posixlt value.

my time value begins character.

a <- "02:57" 

then use strptime convert character posixlt class. within strptime, use conversion specification %l, according strptime help, displays "12-hour clock time single digits preceded blank".

b <- strptime(x = a, tz = "utc", format = "%l") 

the variable b posixlt value, , consists of "current date" + "02:57:00" + "local time zone". can live date , time zone, leading 0 of 12-hour time value remains.

how can eliminate leading 0 of 12-hour time value , still retain posixlt class?

i appreciate insight.

i use lubridate, excellent package working posixlt time objects.

library(lubridate)  <- "02:57" b <- hm(a) 

yields

> b [1] "2h 57m 0s" 

no pesky 0 , sooo other time goodness boot. luck.