PHP, Structures and Functions, STRINGS

If $str1 is less than $str2 this function retuns an integer less than ZERO.

If $str1 is equal to $str2 this function returns ZERO.

If $str1 is greater than $str2 this function returns an an integer greater than ZERO.

This function implements a comparison algorithm that orders alphanumeric STRINGS in the way a human being would, this is described as a natural ordering.

Natural Order String Comparison

This function is binary-safe

This function is CASE SENSITIVE.


<?php

int strnatcmp ( str $str1 , str $str2 )


where,

$str1 = The first STRING to compare 

$str2 = The second STRING to compare

?>

$str1

The first STRING to be compared.

$str2

The second STRING to be compared.

EXERCISE


<?php

$strnccmp01a = "Better late than never!";

$strnccmp01b = "BETTER LATE THAN NEVER!";

$lenght01 = 6;
// 6 initial characters

$intnccmp01ab = strnatcmp($strnccmp01a, 
                                  $strnccmp01b);

if ($intnccmp01ab > 0)
{
echo substr($strnccmp01a, 0, $lenght01)  . 
'<br>is GREATER than<br>' . 
substr($strnccmp01b, 0, $lenght01);
}
elseif ($intnccmp01ab < 0)
{
echo substr($strnccmp01a, 0, $lenght01) . 
'<br>is LESS than<br>' . 
substr($strnccmp01b, 0, $lenght01);
}
else
{
echo substr($strnccmp01a, 0, $lenght01) . 
'<br>is EQUAL to<br>' . 
substr($strnccmp01b, 0, $lenght01);
}

?>

EXERCISE


<?php  

$tst02 = glob('' . "*{.JPG,.jpg,.txt,.TXT,
                             .mp3,.MP3,
                             .wav,.WAV,
                             .m4a,.M4A}", GLOB_BRACE); 

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -   
   This code retrieves all files in the  
   specified directory, if they are: 
   .JPG,.jpg,.txt,.TXT,.mp3, .MP3, .wav, .WAV, .m4a, .M4A  
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 

usort($tst02, "strnatcmp");

foreach($tst02 as $ts02)
{
echo basename($ts02) . '<br>';
}    

?>

EXERCISE


<?php

echo "Testing strnatcmp() : basic functionality.<br>";

$a1 = "abc1";
$b1 = "abc10";
$c1 = "abc15";
$d1 = "abc2";

$a2 = "ABC1";
$b2 = "ABC10";
$c2 = "ABC15";
$d2 = "ABC2";

function str_natcmp($par01, $par02)
{
    $natcmp = strnatcmp($par01, $par02);
    
    if($natcmp > 0)
    {
    echo "<br>$par01<br>is GREATER than<br>$par02<br>";    
    }
    elseif($natcmp == 0)
    {
    echo "<br>$par01<br>is EQUAL to<br>$par02<br>";    
    }
    elseif($natcmp < 0)
    {
    echo "<br>$par01<br>is LESS than<br>$par02<br>";    
    }
    
}

echo "- - -<br>Less than tests:<br>";
str_natcmp($a1, $b1);
str_natcmp($a1, $c1);
str_natcmp($a1, $d1);
str_natcmp($b1, $c1);
str_natcmp($d1, $c1);
echo '<br>- - - <br><br>';
str_natcmp($a1, $b2);
str_natcmp($a1, $c2);
str_natcmp($a1, $d2);
str_natcmp($b1, $c2);
str_natcmp($d1, $c2);

echo "<br>- - - <br><br>Equal to tests;<br>";
str_natcmp($b1, $b1);
str_natcmp($b1, $b2);

echo "<br>- - - <br><br>Greater than tests:<br>";
str_natcmp($b1, $a1);
str_natcmp($c1, $a1);
str_natcmp($d1, $a1);
str_natcmp($c1, $b1);
str_natcmp($c1, $d1);
echo '<br>- - - <br><br>';
str_natcmp($b1, $a2);
str_natcmp($c1, $a2);
str_natcmp($d1, $a2);
str_natcmp($c1, $b2);
str_natcmp($c1, $d2);

?>

EXERCISE


<?php

echo "Testing strnatcmp() function 
            whitespace, left-align, digit.";
echo "<br><br>Leading whitespace, 
                        digits, string 1 longer:<br>";

$str1 = " 00";
$str2 = " 0";

var_dump( strnatcmp( $str1, $str2) );

echo "<br><br>Leading whitespace, 
                       digits, string 2 longer:<br>";

var_dump( strnatcmp( $str2, $str1) );

?>