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Re: Help with a function to return the 'age' of itself

  • To: mathgroup at smc.vnet.net
  • Subject: [mg61435] Re: Help with a function to return the 'age' of itself
  • From: albert <awnl at arcor.de>
  • Date: Wed, 19 Oct 2005 02:16:13 -0400 (EDT)
  • Organization: Arcor
  • References: <dj2662$b76$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,

Just one possibility of many:

$starttime = None; 
timer := If[$starttime === None,
    $starttime = AbsoluteTime[]; 0., 
    AbsoluteTime[] - $starttime
    ]; 

using the following you can reset the timer:

SetAttributes[reset, HoldAll]
reset[timer] := $starttime = None; 

reset[timer]
timer
Pause[3]
timer

actually I would prefer the following, so that it is more clear timer is a
function (note that reset does not need to have the Attribute HoldAll in
this case, and you don't necessarily need an extra symbol to store the
start-value):

timer[0] = None;
timer[] := If[timer[0] === None, 
                 timer[0] = AbsoluteTime[]; 0., 
                 AbsoluteTime[] - timer[0]
           ];
reset[timer] := timer[0] = None;

reset[timer]
timer[]
Pause[2]
timer[]


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