Convert ISO 8601 duration string to seconds

[bdunsmoor]

I'm loading data that is formatted as ISO 8601 duration string.  Below are some samples from the data set. 

Each string always starts with "P," which designates Period, and "T" which designates Time.  The rest of the string  may contain H (Hours), M (Minutes) or S (Seconds) along with numbers for each time element.  

For example, the string "PT1H3M11.312S" represents 1 hour, 3 minutes, 11.312 seconds, which translates to 3791 seconds.  

Question: is there a script function that will convert an ISO 8601 duration string to seconds?  

I'm hoping there is a function so that I won't have to parse out the time elements individually.

Samples from my data:

inboundTalkTime

PT0S

PT1H3M11.312S

PT1H10M21.892S

PT1H15M56.944S

PT1H20M7.027S

PT1H39M18.652S

PT1H49M33.105S

PT18M15.285S

PT42M38.344S

PT54M0.343S

[petter]

I can't give you a single function - but maybe a single expression might do the trick:

[petter · Accepted solution]

If you need to reuse the expression it would be better defined as a variable-that-takes-parameters (function):

[bdunsmoor]

Thank you Peter.  That's worked perfectly.