cvs commit: perlfaq perlfaq4.pod

cvsuser     03/01/03 12:06:21

  Modified:    .        perlfaq4.pod
  Log:
  * How do I find the first array element for which a condition is true?
     + the first assignment should be to the variable which
     remembers the found index, which is $index, not $i (the trial
     index).
  
  * How do I permute N elements of a list?
     + added a faster running example (from Benjamin Goldberg)
  
  Revision  Changes    Path
  1.39      +10 -2     perlfaq/perlfaq4.pod
  
  Index: perlfaq4.pod
  ===================================================================
  RCS file: /cvs/public/perlfaq/perlfaq4.pod,v
  retrieving revision 1.38
  retrieving revision 1.39
  diff -u -w -r1.38 -r1.39
  --- perlfaq4.pod	6 Dec 2002 07:40:11 -0000	1.38
  +++ perlfaq4.pod	3 Jan 2003 20:06:21 -0000	1.39
  @@ -1,6 +1,6 @@
   =head1 NAME
   
  -perlfaq4 - Data Manipulation ($Revision: 1.38 $, $Date: 2002/12/06 07:40:11 $)
  +perlfaq4 - Data Manipulation ($Revision: 1.39 $, $Date: 2003/01/03 20:06:21 $)
   
   =head1 DESCRIPTION
   
  @@ -1280,7 +1280,7 @@
   and check the array element at each index until you find one
   that satisfies the condition.
   
  -	my( $found, $i ) = ( undef, -1 );
  +	my( $found, $index ) = ( undef, -1 );
       for( $i = 0; $i < @array; $i++ )
       	{
           if( $array[$i] =~ /Perl/ )
  @@ -1455,6 +1455,14 @@
   	while (my @perm = $p_iterator->next) {
   	   print "next permutation: (@perm)\n";
   	}
  +
  +For even faster execution, you could do:
  +
  +   use Algorithm::Permute;
  +   my @array = 'a'..'d';
  +   Algorithm::Permute::permute {
  +      print "next permutation: (@array)\n";
  +   } @array;
   
   Here's a little program that generates all permutations of
   all the words on each line of input. The algorithm embodied