etwrite(x,format)

Interprets the input x as a real number of days, and writes it as an elapsed time according to the specified format. The value x must be a real (floating-point) number < 2400; to convert an integer to real, use the $real transform. The elapsed time can be specified in any combination of hours, minutes, seconds, milliseconds, and fractions, but cannot include days, months, or years. The format is as described in dtread(string[,format]) with one addition: the symbol f indicates fractions of hours or fractions of minutes, whichever was immediately preceding; f means there is exactly one digit, ff means there are exactly two digits, and fff means there are exactly three digits. The output is a string variable. For example,

$etwrite(.75,'hh:mm') = '18:00'

$etwrite(.49,'hh:mm') = '11:45'

$etwrite(.49,'h.ff') = '11.75'