chop(), trim(), ltrim(), and rtrim() do not remove \v, \r, or \n.

# chop();

echo "<p><pre>                chop()";
echo "<br>                ------------------<br>";
$x = "     ab cd ef     \v\r\n" ;
echo strlen($x) . " characters: |" . $x . "|<br>";
$y = chop($x);
echo strlen($y) . " characters: |" . $y . "|</pre></p>";

# ltrim();

echo "<p><pre>                ltrim()";
echo "<br>                ------------------<br>";
$x = "\v\r\n     ab cd ef     " ;
echo strlen($x) . " characters: |" . $x . "|<br>";
$y = ltrim($x);
echo strlen($y) . " characters: |" . $y . "|</pre></p>";

# rtrim();

echo "<p><pre>                rtrim()";
echo "<br>                ------------------<br>";
$x = "     ab cd ef     \v\r\n" ;
echo strlen($x) . " characters: |" . $x . "|<br>";
$y = rtrim($x);
echo strlen($y) . " characters: |" . $y . "|</pre></p>";

#
# trim();

echo "<p><pre>                trim()";
echo "<br>                ------------------<br>";
$x = "  \v\r\n   ab cd ef  \v\r\n   " ;
echo strlen($x) . " characters: |" . $x . "|<br>";
$y = trim($x);
echo " " . strlen($y) . " characters: |" . $y . "|</pre></p>";