STRIP whitespaces and selected characters from the beginning and the end of a STRING.
<?php
str trim ( str $str [, str $character_mask ] )
where,
$str = The input STRING
$character_mask = The list of additional characters
to strip from the beginning and the end
?>
| DEFAULT | ASCII | VALUE | |
| " " | 32 | 0x20 | ESPAÇO |
| "\t" | 9 | 0x09 | TAB H |
| "\n" | 10 | 0x0A | NL |
| "\r" | 13 | 0x0D | CR |
| "\0" | 0 | 0x00 | NULL |
| "\x0B" | 11 | 0x0B | TAB V |
| ed48 | |||
EXERCISE
<?php
$strl01a = ' QUOSQUE TANDEM? ';
$strl01b = trim($strl01a);
echo $strl01b . '<br><br>';
$strl01c = ' QUOSQUE TANDEM? ';
$strl01d = trim($strl01c);
echo $strl01d;
?>
EXERCISE
<?php
$strl02a = '-/--//---///----QUOSQUE TANDEM?-/--//---///----';
$strl02b = trim($strl02a, '"-", "/"');
echo $strl02b . '<br><br>';
/* ---------------------------------------
list of characters defined by
a range of ASCII hexadecimal values
'0x29,..0x30' -> from 0x29 to 0x30
--------------------------------------- */
$strl02c = '-/--//---///----QUOSQUE TANDEM?-/--//---///----';
$strl02d = trim($strl02c, '0x29, ..0x30');
echo $strl02d;
?>
EXERCISE
<?php
$tests = <<<TESTS
'ABC' === trim('ABC')
'ABC' === ltrim('ABC')
'ABC' === rtrim('ABC')
'ABC' === trim(" \\0\\t\\nABC \\0\\t\\n")
"ABC \\0\\t\\n" === ltrim(" \\0\\t\\nABC \\0\\t\\n")
" \\0\\t\\nABC" === rtrim(" \\0\\t\\nABC \\0\\t\\n")
" \\0\\t\\nABC \\0\\t\\n" === trim(" \\0\\t\\nABC \\0\\t\\n",'')
" \\0\\t\\nABC \\0\\t\\n" === ltrim(" \\0\\t\\nABC \\0\\t\\n",'')
" \\0\\t\\nABC \\0\\t\\n" === rtrim(" \\0\\t\\nABC \\0\\t\\n",'')
"ABC\\x50\\xC1" === trim("ABC\\x50\\xC1\\x60\\x90","\\x51..\\xC0")
"ABC\\x50" === trim("ABC\\x50\\xC1\\x60\\x90","\\x51..\\xC1")
"ABC" === trim("ABC\\x50\\xC1\\x60\\x90","\\x50..\\xC1")
"ABC\\x50\\xC1" === trim("ABC\\x50\\xC1\\x60\\x90","\\x51..\\xC0")
"ABC\\x50" === trim("ABC\\x50\\xC1\\x60\\x90","\\x51..\\xC1")
"ABC" === trim("ABC\\x50\\xC1\\x60\\x90","\\x50..\\xC1")
TESTS;
include(__DIR__ . '/quicktester.inc');
?>
<?php
/*
// quicktester.inc
Helper for simple tests to check return-value. Usage:
$tests = <<<TESTS
expected_return_value === expression
2 === 1+1
4 === 2*2
FALSE === @ fopen('non_existent_file')
TESTS;
include( 'tests/quicktester.inc' );
Expect: OK
Remember to NOT put a trailing ; after a line!
*/
error_reporting(E_ALL);
$tests = explode("\n",$tests);
$success = TRUE;
foreach ($tests as $n=>$test)
{
// ignore empty lines
if (!$test) continue;
// warn for trailing ;
if (substr(trim($test), -1, 1) === ';') {
echo "WARNING: trailing ';' found in test ".($n+1)."\n";
exit;
}
// try for operators
$operators = array('===', '~==');
$operator = NULL;
foreach ($operators as $a_operator) {
if (strpos($test, $a_operator)!== FALSE) {
$operator = $a_operator;
list($left,$right) = explode($operator, $test);
break;
}
}
if (!$operator) {
echo "WARNING: unknown operator in '$test' (1)\n";
exit;
}
$left = eval("return ($left );");
$right = eval("return ($right);");
switch (@$operator) {
case '===': // exact match
$result = $left === $right;
break;
case '~==': // may differ after 12th significant number
if ( !is_float($left ) && !is_int($left )
|| !is_float($right) && !is_int($right)) {
$result = FALSE;
break;
}
$result = abs(($left-$right) / $left) < 1e-12;
break;
default:
echo "WARNING: unknown operator in '$test' (2)\n";
exit;
}
$success = $success && $result;
if (!$result) {
echo "\nAssert failed:\n";
echo "$test\n";
echo "Left: ";var_dump($left );
echo "Right: ";var_dump($right);
}
}
if ($success) echo "OK";
EXERCISE
<?php
/* trim with unset/null/boolean variable -
* returns an empty string */
$null_var = NULL;
var_dump( trim($null_var) );
echo "<br><br>";
$null_var = "";
var_dump( trim($null_var) );
echo "<br><br>";
$null_var = 0;
var_dump( trim($null_var) );
echo "<br><br>";
$bool_val = true;
var_dump( trim($null_var) );
echo "<br><br>";
/* second argument charlist as null -
* does not trim any white spaces */
var_dump( trim("\ttesting trim", "") );
echo "<br><br>";
var_dump( trim(" \ttesting trim ", NULL) );
echo "<br><br>";
var_dump( trim("\ttesting trim ", true) );
/* Use of class and objects */
echo "<br><br>Testing with OBJECTS:<br>";
class string1
{
public function __toString() {
return "Object";
}
}
$obj = new string1;
var_dump( trim($obj, "Ot") );
/* String with embedded NULL */
echo "<br><br>Testing with String
with embedded NULL:<br>";
var_dump( trim("\x0n1234\x0005678
\x0000efgh\xijkl\x0n1", "\x0n1") );
/* heredoc string */
$str = <<<EOD
us
ing heredoc string
EOD;
echo "<br><br>Testing with heredoc string:<br>";
var_dump( trim($str, "us\ning") );
?>
EXERCISE
<?php
echo "Testing trim() : basic functionality.<br>";
$text = " \t\r\n\0\x0B ---These are a few words--- \t\r\n\0\x0B ";
$hello = "!===Hello World===!";
$binary = "\x0A\x0DExample string\x0A\x0D";
echo "<br><br>Trim string with all white space characters:<br>";
var_dump(trim($text));
echo "<br><br>Trim non-whitespace from a string:<br>";
var_dump(trim($hello, "=!"));
echo "<br><br>Trim some non-white space characters
from a string:<br>";
var_dump(trim($hello, "Hdle"));
echo "<br><br>Trim the ASCII control characters
at the beginning of a string:<br>";
var_dump(trim($binary, "\x00..\x1F"));
?>
EXERCISE
<?php
echo "Testing trim() : error conditions.<br>";
$hello = " Hello World\n";
echo "<br><br>Test trim function with
various invalid charlists:<br>";
var_dump(trim($hello, "..a"));
echo "<br><br>";
var_dump(trim($hello, "a.."));
echo "<br><br>";
var_dump(trim($hello, "z..a"));
echo "<br><br>";
var_dump(trim($hello, "a..b..c"));
?>