for midnightStandard2, a POSIXct object with time
zone "GMT".
Arguments
charvec
a character string or vector of dates and times.
format
a string, the format specification of the input character vector.
Details
midnightStandard2() calls strptime. Since the
latter returns NAs for elements that don't conform to the
midnight standard, the inputs corresponding to NAs are further
processed to fix this.
midnightStandard() converts to character vector the result
obtained from midnightStandard2().