http://qs1969.pair.com?node_id=11139196

dnamonk has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks, I have a general logic question. I need help in logic and not code. I have a question about recalling my function within a loop. Below is my code: 

List_new = myfunction()
for items in List_new:
    if(my condition is TRUE):
        Execute some commands
    if(my condition is FALSE):
        recall myfunction()

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My problem is that I am loading "List_new" using myfunction(). How can I change "List_new" iteratively when my condition is False. I want to reload the function especially when the condition is FALSE. This means I keep calling the function until it is false and then execute the final output from myfunction(). Thank you in advance for your help.

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Re: Recalling a function iteratively
by tybalt89 (Monsignor) on Nov 29, 2021 at 03:16 UTC

    In untested pseudo-perl 

    my @list_new = myfunction();
while( @list_new )
    {
    my $item = shift @list_new;
    if( conditiontrue ) { execute($item); }
    if( conditionfalse ) { @list_new = myfunction(); }
    }

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[d/l]
      Thank you for the advice :)
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Re: Recalling a function iteratively
by NetWallah (Canon) on Nov 29, 2021 at 03:17 UTC
    Your "Logic" is too fuzzy to respond meaningfully.

    It is a bad idea to iterate over a list, and attempt to modify the list during the iteration.

    My advice is to define a deterministic termination condition, and put your logic in a "while" loop.

                    "If you had better tools, you could more effectively demonstrate your total incompetence."

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Re: Recalling a function iteratively
by AnomalousMonk (Archbishop) on Nov 29, 2021 at 05:05 UTC

    Here's my guess: 

    c:\@Work\Perl>perl -wMstrict -le
"use List::MoreUtils qw(any);
 ;;
 sub myfunc { return map { int rand 10 } 1 .. $_[0]; }
 ;;
 my @List_new;
 ;;
 UNTIL_TRUE: {
   @List_new = myfunc(7);
   any { $_ == 3 } @List_new or redo UNTIL_TRUE;
   }
 ;;
 print qq{@List_new};
"
0 1 6 1 8 1 3

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    Notes:
    • List::MoreUtils::any() can be replaced with the built-in grep for short lists (for some definition of "short").
    • any() may also be found in List::Util in later versions of Perl.
    • The label UNTIL_TRUE is not needed, it's just documentary.

    Give a man a fish:  <%-{-{-{-<

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