This function is a character by character translation and if you want to perform more complex operations you can use the s/// regex substitution operator instead. In Perl tr/// is known better as an operator rather than a function.

The syntax form of the tr/// operator is as follows:

tr/SEARCHLIST/REPLACEMENTLIST/cds

The c, d, s are modifiers that add additional functionality to the Perl tr/// operator:

• c - is used to specify that the SEARCHLIST character set is complemented
• d - is used to delete found but not replaced characters
• s - is used to specify that the sequences of characters that were transliterated to the same character are squashed down to a single instance of the character

The slash (/) has the meaning of a delimiter, because it separates the arguments of the tr/// operator. However, you can replace it with whatever sign of punctuation you want. The syntax changes a little if you use parentheses because they include the idea of containment.

For instance, the following syntax forms of the Perl tr/// operator are equivalents and do the same thing (it replaces any lowercase character from a to f with digits from 2 to 7 and any character from g to z with the 7 digit):

$str =~ tr/a-z/2-7/;
$str =~ tr:a-z:2-7:;
$str =~ tr[a-z][2-7];
$str =~ tr(a-z)(2-7);
$str =~ tr<2-7>;

To illustrate how to use this operator, look at the following example which shows you how you can use the tr/// operator wih the =~ binding operator:

my $string = 'one two three four five six seven';
$string =~ tr/a-z/A-Z/;

print "$string\n";
# it prints: ONE TWO THREE FOUR FIVE SIX SEVEN

to see a lot of fully commented examples that help you use the tr/// function in your scripts.