[oracle@jhoa 14]$ cat a3.pl 
@array=qw/a b c d e f g/;
$var = join("9",@array);
print "\$var is $var\n";

[oracle@jhoa 14]$ perl a3.pl 
$var is a9b9c9d9e9f9g


   join EXPR,LIST
               Joins the separate strings of LIST into a single string with fields
               separated by the value of EXPR, and returns that new string.  Exam-
               ple:

                   $rec = join(':', $login,$passwd,$uid,$gid,$gcos,$home,$shell);

               Beware that unlike "split", "join" doesn't take a pattern as its
               first argument.  Compare "split".

join 表达式,列表

拼接函数