Duration in seconds
S = seconds( returns
an array of seconds equivalent to the values in X)X.
If X is a numeric array, then S is
a duration array in units of seconds.
If X is a duration array,
then S is a double array with
each element equal to the number of seconds in the corresponding element
of X.
The seconds function converts between duration and double values.
To display a duration in units of seconds, set its Format property
to 's'.