RETURN the information about number of characters used in a STRING.
<?php
mix count_chars ( str $string [, int $mode = 0 ] )
where,
$string = The string to be examined
$mode = To control the format of returned values
( SEE the below TABLE )
?>
| VALUE | WHAT RETURN |
| 0 | an array with the byte-value as key and the frequency of every byte as value |
| 1 | same as 0 but only byte-values with a frequency greater than zero are listed |
| 2 | same as 0 but only byte-values with a frequency equal to zero are listed |
| 3 | a string containing all unique characters is returned |
| 4 | a string containing all not used characters is returned |
| ed48 | |
EXERCISE
<?php
$txta = "The quick brown fox jumps over the lazy dog.";
echo $txta;
echo '<br><br><br>';
$itblei = '<div class="circ bfff">
<table width="100%" cellspacing="5" cellpadding="5"
border="1" align="center">
<tbody>';
$tit0 = '<tr><td colspan="3">ALL ( MODE 0 )</td></tr>';
$tit1 = '<tr>
<td colspan="3">EFFECTIVE OCCURRENCES ( MODE 1 )
</td></tr>';
$tit2 = '<tr><td colspan="3">NOT USED ( MODE 2 )</td></tr>';
$tit3 = 'EFFECTIVE OCCURRENCES ( MODE 3 )';
$tit4 = 'NOT USED ( MODE 4 )';
$itblee = '<tr><td width="33%">ASCII #</td>
<td width="33%">CHARACTER</td>
<td width="34%"># REPETITIONS</td></tr>';
$etble = '<tr>
<td colspan="3">ed48</td></tr>
</tbody></table></div><br>';
// mode = 0
// ARRAY -> ASCII CHARACTERS ε[ 0, 255 ] - ALL
$count0 = count_chars($txta);
echo $itblei . $tit0 . $itblee;
foreach($count0 as $cnt0 => $cn0)
{
echo '<tr><td>' . $cnt0 . '</td><td>' .
chr($cnt0) . '</td><td>' . $cn0 .
'</td></tr>';
}
echo $etble . '<br>';
// mode = 1
// ARRAY -> ASCII CHARACTERS ε[ 0, 255 ]
// - EFFECTIVE OCCURRENCES
$count1 = count_chars($txta, 1);
echo $itblei . $tit1 . $itblee;
foreach($count1 as $cnt1 => $cn1)
{
echo '<tr><td>' . $cnt1 . '</td><td>' .
chr($cnt1) . '</td><td>' . $cn1 .
'</td></tr>';
}
echo $etble . '<br>';
// mode = 2
// ARRAY -> ASCII CHARACTERS ε[ 0, 255 ]
// - NOT USED
$count2 = count_chars($txta, 2);
echo $itblei . $tit2 . $itblee;
foreach($count2 as $cnt2 => $cn2)
{
echo '<tr><td>' . $cnt2 . '</td><td>' .
chr($cnt2) . '</td><td>' . $cn2 .
'</td></tr>';
}
echo $etble . '<br>';
// mode = 3
// STRING -> ASCII CHARACTERS ε[ 0, 255 ]
// - EFFECTIVE OCCURRENCES
$count3 = count_chars($txta, 3);
echo $tit3 . '<br>' . $count3 . '<br><br>';
// mode = 4
// STRING -> ASCII CHARACTERS ε[ 0, 255 ]
// - NOT USED
$count4 = count_chars($txta, 4);
echo $tit4 . '<br>' . $count4;
?>
EXERCISE
<?php
echo "Testing count_chars() : basic functionality.<br><br>";
$string = "Return information about
characters used in a string.";
echo "<br><br>$string<br><br>";
var_dump(count_chars($string));
echo '<br><br>';
var_dump(count_chars($string, 0));
echo '<br><br>';
var_dump(count_chars($string, 1));
echo '<br><br>';
var_dump(count_chars($string, 2));
echo '<br><br>';
var_dump(count_chars($string, 3));
echo '<br><br>';
var_dump(count_chars($string, 4));
try {
count_chars($string, 5);
} catch (ValueError $e) {
echo $e->getMessage(), "<br>";
}
?>