We have two syntax forms for this function:

lc EXPR 
lc

to see a lot of fully commented examples that help you use the Perl statements and the Perl buit-in functions in your scripts.

# initialize some string variable
my $str = "What is Perl Language for";
lc($str);
print $str, "\n";
# displays: What is Perl Language for
$str = lc($str);
print $str, "\n";
# displays: what is perl language for

Perl lc function is very useful when you need to perform some string comparisons against some string variables. Bear in mind that all string comparisons are case sensitive and the following strings "Perl" and "perl" are not the same. As a parenthesis, don’t ever use numerical operators in string comparisons, because it’s for sure the result will not be the one you would expect.

Now let’s get back to our comparisons. If you want to compare two string variables case insensitive using lc function, you may have at least two choices:

• Convert both strings in lowercase using an assignment operator and than make the comparisons
• Compare the strings by calling the lc function for each of them, without changing their values

#comparison using the assignment operator
my $str1 = " rose";
my $str2 = " ROSE";
$str1 = lc($str1);
$str2 = lc($str2);
if($str1 eq $str2) {
  print "The two strings are equal\n";
}

#comparison without altering the string values

$str1 = " rose";
$str2 = " ROSE";
if(lc($str1) eq lc($str2)) {
  print "The two strings are equal\n";
}