#!/usr/bin/perl -w
#######################  The Translate Operator  ###########################
$var = "aBcDeFg";
$var =~ tr/A-Z/a-z/;     ######  Effectively like lc().
print "$var\n";

$var = "0A2#B!C";
$var =~ tr/A-Z/X/c;      ######  Replace non-upcases with X (XAXXBXC).
print "$var\n";

$var = "0A2#B!C";
$var =~ tr/A-Z/X/cs;     ######  Same as previous tr but makes XX become X.
print "$var\n";

$var = "12xyz45abc6";    ######  Delete all digits (xyzabc).
$var =~ tr/0-9//d;
print "$var\n";

$var = "12xyz45abc6";    ######  Delete all NON-digits (12456).
$var =~ tr/0-9//cd;
print "$var\n";

$_ = $var = "12xyz45abc6";  ######  Count of digits in $_ (5).
$newvar = tr/0-9//;         ######  Notice we use "=" not "=~".
print "$newvar\n";

$newvar = $var =~ tr/0-9//; ######  Same thing but counts digits in $var.
print "$newvar\n";

$var = "0123456789";
$var =~ tr/0-9/W-Z/;        ######  Right list padded by last char (Z).
print "$var\n";             ######  Result is WXYZZZZZZZ.

$var = "0123456789";
$var =~ tr/0-9/W-Z/d;       ######  Translate but DELETE elements in left
print "$var\n";             ######  list that are not in the right (WXYZ).

$var = "0004444566662221";  ######  Squeeze identical consecutive digits.
$var =~ tr/0-9//s;          ######  Result: 045621.
print "$var\n";

$var = "a\001bcd\007ef\017gh\007";
print "$var\n";
$var =~ tr/\001-\020//d;    ######  You can use \n,\t,\f in tr but tr knows 
print "$var\n";             ######  NOTHING about regular expressions! 
#######################  Results of Execution Below  ######################

abcdefg
XAXXBXC
XAXBXC
xyzabc
12456
5
5
WXYZZZZZZZ
WXYZ
045621
a
bcdefgh
abcdefgh