But I anticipated a bit, for this function two syntax forms are available:

length EXPR
length

You can either omit the parentheses or not, sometimes it is healthy to put it in order to remove any ambiguity. In the below code sample we’ll show you how to use it.

Example 1.

# define a string variable 
my $strVar = "A simple example of a string variable";
# get the length of the string
my $strLength = length($strVar);
# print the length
print "Our string has $strLength characters\n";
# it prints: Our string has 37 characters

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

Please note that Perl length function is for characters, so if you use a Unicode expression, it will return the number of characters and not the number of bytes. However, you can get the length of a string in bytes as you can see in the next snippet code:

# define a string variable
my $chars = "\x{2603}\x{2602}";
{
  use bytes;
  print "Length in bytes: ", length($chars), "\n";
}
print "Length in characters: ", length($chars), "\n";

• the string variable $chars contains two Unicode characters: 2603 (which is a snowman) and 2602 (an umbrella) and I used hexadecimal escapes to represent them. A hexadecimal escape begins with \x and it is either followed by two digit hexadecimal number (for example "\x31" is "1") or a hexadecimal of arbitrary length included in curly braces (\x{2603})
• I used bytes pragma to get the string length in bytes and I included it in a block in order to limit its effect to the scope of the block
• I printed the length of the string both in bytes and in characters

If we run this code we get the following output:

Length in bytes: 6
Length in characters: 2

I’ll show you next a short code sample that reads some lines of text from STDIN. We use Perl length function to find the shortest and the longest string line:

my $minStrLength = "";
my $maxStrLength = "";
while(<STDIN>)
{
  chomp;
  if($minStrLength eq "")
  {
    $minStrLength = $maxStrLength = $_;    
    next;
  }
  if(length $_ < length $minStrLength)
  {
    $minStrLength = $_; 
    next;   
  }
  if(length $_ > length $maxStrLength)
  {
    $maxStrLength = $_; 
  }
}

print "Str min: $minStrLength\n";
print "Str max: $maxStrLength\n";

Example 4.

The last example will show you how to use the Perl length function in connection with arrays and sort function. We want to sort the words of a string in a descending length order and next print it. See the code for more details:

# create and initialize a string
my $str = "Here are a few Perl functions";
# split the string in an array
my @array = split(' ',$str);
# sort the array by descending value length
@array = sort { length $b cmp length $a } @array;
# convert back the array to string
$str = join ' ', @array;
# print the string
print "$str\n";

functions Here Perl are few a

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