打印上三角或下三角矩阵（9x9） - perl, R

欲打印矩阵位置示意图

 #!/usr/bin/perl -w
 use strict;

 ##  bottom left
 for my $row (..)
 {
     for my $col(..)
     {
         if($col <= $row)
         {
             print $row * $col, "\t";
         }
         else
         {
             print " \t";
         }
     }
     print "\n";
 }
 print "-" x  , "\n";

 ## top left
 for my $row (reverse(..))
 {
     for my $col(..)
     {
         if($col <= $row)
         {
             print $row * $col, "\t";
         }
         else
         {
             print " \t";
         }
     }
     print "\n";
 }

输出：

 ## bottom right
 for my $row (reverse(..))
 {
     for my $col(..)
     {
         #print $row * $col, "\t";
         if($col >= $row)
         {
             print $row * $col, "\t";
         }
         else
         {
             print " \t";
         }
     }
     print "\n";
 }
 print "-" x  , "\n";

 ## top right
 for my $row (..)
 {
     for my $col(..)
     {
         if($col >= $row)
         {
             print $row * $col, "\t";
         }
         else
         {
             print " \t";
         }
     }
     print "\n";
 }

输出：

R 取上下三角矩阵（top right， bottom left）就简单的多，有函数可以直接用！

upper.tri()

lower.tri()