in reply to Inserting an element into an array after a certain element

Say, you have "a,b,c,d,e" and want a "f" after "c": 
   @array = map { $_ eq "c" ? ("c","f") : $_ } @array

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but this would insert "f" for each "c" you have.

Alberto Simões

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Re^2: Inserting an element into an array after a certain element
by RazorbladeBidet (Friar) on Mar 31, 2005 at 18:58 UTC
    You could easily fix that by adding a counter: 
    @array = map { $_ eq "c" && !$found++ ? ("c","f") : $_ } @array

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    (as a sub) 
     sub insert_after_first {
   my $arr_ref = shift;
   my $to_insert = shift;
   my $insert_after_me = shift;

   my $found = 0;

   map { $_ eq $insert_after_me && !$found++ ? ( $insert_after_me, $to
+_insert ) : $_ } @$arr_ref;
 }

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    "Oh that's just what we call pillow talk, baby, that's all."
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Re^2: Inserting an element into an array after a certain element
by ikegami (Patriarch) on Mar 31, 2005 at 19:07 UTC

    Ajusted to only do it once:

    my $first = 1;
@array = map {
   if ($first && $_ eq "c") {
      $first = 0;
      ($_, "x")
   } else {
      $_
   }
} @array;

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    hum, ugly. How about:

    my $first = 1;
@array = map {
   my @a = $_;
   push(@a, "x") if ($first && $_ eq "c");
   $first ||= @a-1;
   @a
} @array

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    Nope, still ugly. Well, you could always do:

    foreach (0..$#array) {
   if ($array[$_] eq "c") {
      splice(@array, $_+1, 0, "x");
      last;      
   }
}

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Re^2: Inserting an element into an array after a certain element
by nimdokk (Vicar) on Apr 01, 2005 at 19:10 UTC
    Actually, I think this is along the lines of what I'm looking to do with something I'm working on.
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