Easy way to pass in previous array element?

[StormMedic85]

Within a subroutine, I need to pass in two parameters...a current value (which will be passed in from the value array), and the previous value (the element in the value array BEFORE the current element). I need it to do this for every function call. Any suggestions? The array length varies each time the program is ran so I can't simply use @value[x], where x is the element number.

Thanks very much for any help!

 

[travs69]

Something like

@array = qw(this is a test);
print $array[$#array],' ',$array[$#array-1],"\n";

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[StormMedic85]

Thanks! That's extremely helpful and exactly what I want! I'm just having difficulties in incorporating it into my for loop...

for ($i=0; $i<$size; $i++){
$thickness = &layer($altitude[$i],$altitude[$#altitude-1]);
}

I can't do $altitude[$i][$#altitude[$i-1] or I get a syntax error. :-\

Any ideas? Thanks so much!

 

[KevinADC]

Your code makes it look like you are passing all of the array elements to &layer() two at a time. Is that true? If so:

for my $i (1..$#altitude){
   $thickness = &layer($altitude[$i],$altitude[$i-1]);
}

but unless you are doing something with $thickness it will always equal the value returned by the last iteration of the loop.

------------------------------------------
- Kevin, perl coder unexceptional!

 

[StormMedic85]

Thank you VERY much! You're awesome!

 

[MillerH]

Minor simplification:

[olive][b]for[/b][/olive] [url=http://perldoc.perl.org/functions/my.html][black][b]my[/b][/black][/url] [blue]$i[/blue] [red]([/red][fuchsia]1..[/fuchsia][blue]$#altitude[/blue][red])[/red][red]{[/red]
	[blue]$thickness[/blue] = [maroon]layer[/maroon][red]([/red][blue]@altitude[/blue][red][[/red][blue]$i[/blue],[blue]$i[/blue]-[fuchsia]1[/fuchsia][red]][/red][red])[/red][red];[/red]
[red]}[/red]

- Miller

 

[PaulTEG]

At a glance it looks like you'll miss out on the first data point, but you won't have a previous reference point, is this what you want?

Paul
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