Type Juggling

PHP does not require explicit type definition in variable declaration. In this case, the type of a variable is determined by the value it stores. That is to say, if a string is assigned to variable $var, then $var is of type string. If afterwards an int value is assigned to $var, it will be of type int.

PHP may attempt to convert the type of a value to another automatically in certain contexts. The different contexts which exist are:

  • Numeric
  • String
  • Logical
  • Integral and string
  • Comparative
  • Function

Note: When a value needs to be interpreted as a different type, the value itself does not change types.

To force a variable to be evaluated as a certain type, see the section on Type casting. To change the type of a variable, see the settype() function.

Numeric contexts

This is the context when using an arithmetical operator.

In this context if either operand is a float (or not interpretable as an int), both operands are interpreted as floats, and the result will be a float. Otherwise, the operands will be interpreted as ints, and the result will also be an int. As of PHP 8.0.0, if one of the operands cannot be interpreted a TypeError is thrown.

String contexts

This is the context when using echo, print, string interpolation, or the string concatenation operator.

In this context the value will be interpreted as string. If the value cannot be interpreted a TypeError is thrown. Prior to PHP 7.4.0, an E_RECOVERABLE_ERROR was raised.

Logical contexts

This is the context when using conditional statements, the ternary operator, or a logical operator.

In this context the value will be interpreted as bool.

Integral and string contexts

This is the context when using a bitwise operators.

In this context if all operands are of type string the result will also be a string. Otherwise, the operands will be interpreted as ints, and the result will also be an int. As of PHP 8.0.0, if one of the operands cannot be interpreted a TypeError is thrown.

Comparative contexts

This is the context when using a comparison operator.

The type conversions which occur in this context are explained in the Comparison with Various Types table.

Function contexts

This is the context when a value is passed to a typed parameter, property, or returned from a function which declares a return type.

In this context the value must be a value of the type. Two exceptions exist, the first one is: if the value is of type int and the declared type is float, then the integer is converted to a floating point number. The second one is: if the declared type is a scalar type, the value is convertable to a scalar type, and the coercive typing mode is active (the default), the value may be converted to an accepted scalar value. See below for a description of this behaviour.

Warning

Internal functions automatically coerce null to scalar types, this behaviour is DEPRECATED as of PHP 8.1.0.

Coercive typing with simple type declarations

  • bool type declaration: value is interpreted as bool.
  • int type declaration: value is interpreted as int if the conversion is well-defined. For example the string is numeric.
  • float type declaration: value is interpreted as float if the conversion is well-defined. For example the string is numeric.
  • string type declaration: value is interpreted as string.

Coercive typing with union types

When strict_types is not enabled, scalar type declarations are subject to limited implicit type coercions. If the exact type of the value is not part of the union, then the target type is chosen in the following order of preference:

  1. int
  2. float
  3. string
  4. bool
If the type exists in the union and the value can be coerced to the type under PHP's existing type-checking semantics, then the type is chosen. Otherwise, the next type is tried.

Caution

As an exception, if the value is a string and both int and float are part of the union, the preferred type is determined by the existing numeric string semantics. For example, for "42" int is chosen, while for "42.0" float is chosen.

Note:

Types that are not part of the above preference list are not eligible targets for implicit coercion. In particular no implicit coercions to the null, false, and true types occur.

Example #1 Example of types being coerced into a type part of the union

<?php
// int|string
42 --> 42 // exact type
"42" --> "42" // exact type
new ObjectWithToString --> "Result of __toString()"
// object never compatible with int, fall back to string
42.0 --> 42 // float compatible with int
42.1 --> 42 // float compatible with int
1e100 --> "1.0E+100" // float too large for int type, fall back to string
INF --> "INF" // float too large for int type, fall back to string
true --> 1 // bool compatible with int
[] --> TypeError // array not compatible with int or string

// int|float|bool
"45" --> 45 // int numeric string
"45.0" --> 45.0 // float numeric string

"45X" --> true // not numeric string, fall back to bool
"" --> false // not numeric string, fall back to bool
"X" --> true // not numeric string, fall back to bool
[] --> TypeError // array not compatible with int, float or bool
?>

Type Casting

Type casting converts the value to a chosen type by writing the type within parentheses before the value to convert.

<?php
$foo
= 10; // $foo is an integer
$bar = (bool) $foo; // $bar is a boolean
?>

The casts allowed are:

  • (int) - cast to int
  • (bool) - cast to bool
  • (float) - cast to float
  • (string) - cast to string
  • (array) - cast to array
  • (object) - cast to object
  • (unset) - cast to NULL

Note:

(integer) is an alias of the (int) cast. (boolean) is an alias of the (bool) cast. (binary) is an alias of the (string) cast. (double) and (real) are aliases of the (float) cast. These casts do not use the canonical type name and are not recommended.

Warning

The (real) cast alias has been deprecated as of PHP 8.0.0.

Warning

The (unset) cast has been deprecated as of PHP 7.2.0. Note that the (unset) cast is the same as assigning the value NULL to the variable or call. The (unset) cast is removed as of PHP 8.0.0.

Caution

The (binary) cast and b prefix exists for forward support. Currently (binary) and (string) are identical, however this may change and should not be relied upon.

Note:

Whitespaces are ignored within the parentheses of a cast. Therefore, the following two casts are equivalent:

<?php
$foo
= (int) $bar;
$foo = ( int ) $bar;
?>

Casting literal strings and variables to binary strings:

<?php
$binary
= (binary) $string;
$binary = b"binary string";
?>

Note: Instead of casting a variable to a string, it is also possible to enclose the variable in double quotes.

<?php
$foo
= 10; // $foo is an integer
$str = "$foo"; // $str is a string
$fst = (string) $foo; // $fst is also a string

// This prints out that "they are the same"
if ($fst === $str) {
echo
"they are the same";
}
?>

It may not be obvious exactly what will happen when casting between certain types. For more information, see these sections:

Note: Because PHP supports indexing into strings via offsets using the same syntax as array indexing, the following example holds true for all PHP versions:

<?php
$a
= 'car'; // $a is a string
$a[0] = 'b'; // $a is still a string
echo $a; // bar
?>
See the section titled String access by character for more information.

add a note

User Contributed Notes 36 notes

up
68
Raja
19 years ago
Uneven division of an integer variable by another integer variable will result in a float by automatic conversion -- you do not have to cast the variables to floats in order to avoid integer truncation (as you would in C, for example):

$dividend = 2;
$divisor = 3;
$quotient = $dividend/$divisor;
print $quotient; // 0.66666666666667
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10
Anonymous
3 years ago
Cast operators have a very high precedence, for example (int)$a/$b is evaluated as ((int)$a)/$b, not as (int)($a/$b) [which would be like intdiv($a,$b) if both $a and $b are integers].
The only exceptions (as of PHP 8.0) are the exponentiation operator ** [i.e. (int)$a**$b is evaluated as (int)($a**$b) rather than ((int)$a)**$b] and the special access/invocation operators ->, ::, [] and () [i.e. in each of (int)$a->$b, (int)$a::$b, (int)$a[$b] and (int)$a($b), the cast is performed last on the result of the variable expression].
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16
Anonymous
5 years ago
"An example of PHP's automatic type conversion is the multiplication operator '*'. If either operand is a float, then both operands are evaluated as floats, and the result will be a float. Otherwise, the operands will be interpreted as integers, and the result will also be an integer. Note that this does not change the types of the operands themselves; the only change is in how the operands are evaluated and what the type of the expression itself is."

I understand what the doc is trying to say here, but this sentence is not correct as stated, other types can be coerced into floats.

e.g.

<?php
$a
= "1.5"; // $a is a string
$b = 100; // $b is an int
$c = $a * $b; // $c is a float, value is 150
// multiplication resulted in a float despite fact that neither operand was a float
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26
fardelian
10 years ago
Casting objects to arrays is a pain. Example:

<?php

class MyClass {

private
$priv = 'priv_value';
protected
$prot = 'prot_value';
public
$pub = 'pub_value';
public
$MyClasspriv = 'second_pub_value';

}

$test = new MyClass();
echo
'<pre>';
print_r((array) $test);

/*
Array
(
[MyClasspriv] => priv_value
[*prot] => prot_value
[pub] => pub_value
[MyClasspriv] => second_pub_value
)
*/

?>

Yes, that looks like an array with two keys with the same name and it looks like the protected field was prepended with an asterisk. But that's not true:

<?php

foreach ((array) $test as $key => $value) {
$len = strlen($key);
echo
"{$key} ({$len}) => {$value}<br />";
for (
$i = 0; $i < $len; ++$i) {
echo
ord($key[$i]) . ' ';
}
echo
'<hr />';
}

/*
MyClasspriv (13) => priv_value
0 77 121 67 108 97 115 115 0 112 114 105 118
*prot (7) => prot_value
0 42 0 112 114 111 116
pub (3) => pub_value
112 117 98
MyClasspriv (11) => second_pub_value
77 121 67 108 97 115 115 112 114 105 118
*/

?>

The char codes show that the protected keys are prepended with '\0*\0' and private keys are prepended with '\0'.__CLASS__.'\0' so be careful when playing around with this.
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25
yury at krasu dot ru
21 years ago
incremental operator ("++") doesn't make type conversion from boolean to int, and if an variable is boolean and equals TRUE than after ++ operation it remains as TRUE, so:

$a = TRUE;
echo ($a++).$a; // prints "11"
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11
miracle at 1oo-percent dot de
18 years ago
If you want to convert a string automatically to float or integer (e.g. "0.234" to float and "123" to int), simply add 0 to the string - PHP will do the rest.

e.g.

$val = 0 + "1.234";
(type of $val is float now)

$val = 0 + "123";
(type of $val is integer now)
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11
rmirabelle
13 years ago
The object casting methods presented here do not take into account the class hierarchy of the class you're trying to cast your object into.

/**
* Convert an object to a specific class.
* @param object $object
* @param string $class_name The class to cast the object to
* @return object
*/
public static function cast($object, $class_name) {
if($object === false) return false;
if(class_exists($class_name)) {
$ser_object = serialize($object);
$obj_name_len = strlen(get_class($object));
$start = $obj_name_len + strlen($obj_name_len) + 6;
$new_object = 'O:' . strlen($class_name) . ':"' . $class_name . '":';
$new_object .= substr($ser_object, $start);
$new_object = unserialize($new_object);
/**
* The new object is of the correct type but
* is not fully initialized throughout its graph.
* To get the full object graph (including parent
* class data, we need to create a new instance of
* the specified class and then assign the new
* properties to it.
*/
$graph = new $class_name;
foreach($new_object as $prop => $val) {
$graph->$prop = $val;
}
return $graph;
} else {
throw new CoreException(false, "could not find class $class_name for casting in DB::cast");
return false;
}
}
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19
Anonymous
21 years ago
Printing or echoing a FALSE boolean value or a NULL value results in an empty string:
(string)TRUE //returns "1"
(string)FALSE //returns ""
echo TRUE; //prints "1"
echo FALSE; //prints nothing!
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9
kuzawinski dot marcin at NOSPAM dot gmail dot com
9 years ago
You REALLY must be aware what you are doing, when you cast a lot in your code. For example, you can accidentaly change FALSE to TRUE (probably not in one line, like here):

if(TRUE === (boolean) (array) (int) FALSE) {
kaboom();
}
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13
ieee at REMOVE dot bk dot ru
11 years ago
There are some shorter and faster (at least on my machine) ways to perform a type cast.
<?php
$string
='12345.678';
$float=+$string;
$integer=0|$string;
$boolean=!!$string;
?>
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5
martinscotta at gmail dot com
13 years ago
in response to bhsmither at gmail.com

It raises a warning because of the bad enquoted variable

<?php

error_reporting
( E_ALL | E_STRICT );

$foo['ten'] = 10; // $foo['ten'] is an array holding an integer at key "ten"
$str = "{$foo['ten']}"; // works "10"
$str = "$foo[ten]"; // DO NOT work!
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2
Dhairya Lakhera
4 years ago
Value of uninitialized variable of different data types.

settype($a,'bool');
var_dump($a); //boolean false

settype($b,'string');
var_dump($b); //string '' (length=0)

settype($c,'array');
var_dump($c); //array (size=0) empty

settype($d,'int');
var_dump($d); //int 0

settype($e,'float');
var_dump($e); //float 0

settype($f,'object');
var_dump($f); //object(stdClass)[1]
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1
hek at theeks dot net
15 years ago
It would be useful to know the precedence (for lack of a better word) for type juggling. This entry currently explains that "if either operand is a float, then both operands are evaluated as floats, and the result will be a float" but could (and I think should) provide a hierarchy that indicates, for instance, "between an int and a boolean, int wins; between a float and an int, float wins; between a string and a float, string wins" and so on (and don't count on my example accurately capturing the true hierarchy, as I haven't actually done the tests to figure it out). Thanks!
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0
Anonymous
12 years ago
namaroulis stated "I found it tricky to check if a posted value was an integer"; to test if a variable is a number or a numeric string (such as form input, which is always a string), you must use is_numeric():

<?php
$_POST
['a'] = "42";

is_numeric( $_POST['a'] ); // true
?>
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0
hemi68 at hotmail dot com
12 years ago
Cast a string to binary using PHP < 5.2.1

$binary = unpack('c*', $string);
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0
jphansen at uga dot edu
12 years ago
Type casting from string to int and vice versa is probably the most common conversation. PHP does this very simply through the +. and .= operators, removing any explicit casting:

<?php
$x
= 1;
var_dump($x); // int(1)
$x .= 1;
var_dump($x); // string(2) "11"; also an empty string ("") would cast to string without changing $x

$x = "1";
var_dump($x); // string(1) "1"
$x += 1;
var_dump($x); // int(2); also a zero value (0) would cast to int without changing $x
?>
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0
namaroulis at gmail dot com
13 years ago
I found it tricky to check if a posted value was an integer.

<?php

$_POST
['a'] = "42";

is_int( $_POST['a'] ); //false
is_int( intval( "anything" ) ); //always true
?>

A method I use for checking if a string represents an integer value.

<?php
function check_int( $str )
{
return
is_numeric( $str ) && intval( $str ) - $str == 0;
}
?>
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0
bhsmither at gmail.com
13 years ago
<?php
$foo
['ten'] = 10; // $foo['ten'] is an array holding an integer at key "ten"
$str = "$foo['ten']"; // throws T_ENCAPSED_AND_WHITESPACE error
$str = "$foo[ten]"; // works because constants are skipped in quotes
$fst = (string) $foo['ten']; // works with clear intention
?>
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0
edgar dot klerks at gmail dot com
15 years ago
It seems (unset) is pretty useless. But for people who like to make their code really compact (and probably unreadable). You can use it to use an variable and unset it on the same line:

Without cast:

<?php

$hello
= 'Hello world';
print
$hello;
unset(
$hello);

?>

With the unset cast:

<?php

$hello
= 'Hello world';
$hello = (unset) print $hello;

?>

Hoorah, we lost another line!
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-1
berniev
8 years ago
May be expected, but not stated ..
Casting to the existing (same) type has no effect.
$t = 'abc'; // string 'abc'
$u=(array) $t; // array 0 => string 'abc' <-- now an array
$v=(array) $u; // array 0 => string 'abc' <-- unchanged
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-1
lucazd at gmail dot com
15 years ago
@alexgr (20-Jun-2008)

Correct me if I'm wrong, but that is not a cast, it might be useful sometimes, but the IDE will not reflect what's really happening:

<?php
class MyObject {
/**
* @param MyObject $object
* @return MyObject
*/
static public function cast(MyObject $object) {
return
$object;
}
/** Does nothing */
function f() {}
}

class
X extends MyObject {
/** Throws exception */
function f() { throw new exception(); }
}

$x = MyObject::cast(new X);
$x->f(); // Your IDE tells 'f() Does nothing'
?>

However, when you run the script, you will get an exception.
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-1
toma at smartsemantics dot com
19 years ago
In my much of my coding I have found it necessary to type-cast between objects of different class types.

More specifically, I often want to take information from a database, convert it into the class it was before it was inserted, then have the ability to call its class functions as well.

The following code is much shorter than some of the previous examples and seems to suit my purposes. It also makes use of some regular expression matching rather than string position, replacing, etc. It takes an object ($obj) of any type and casts it to an new type ($class_type). Note that the new class type must exist:

function ClassTypeCast(&$obj,$class_type){
if(class_exists($class_type,true)){
$obj = unserialize(preg_replace"/^O:[0-9]+:\"[^\"]+\":/i",
"O:".strlen($class_type).":\"".$class_type."\":", serialize($obj)));
}
}
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-2
wbcarts at juno dot com
15 years ago
WHERE'S THE BEEF?

Looks like type-casting user-defined objects is a real pain, and ya gotta be nuttin' less than a brain jus ta cypher-it. But since PHP supports OOP, you can add the capabilities right now. Start with any simple class.
<?php
class Point {
protected
$x, $y;

public function
__construct($xVal = 0, $yVal = 0) {
$this->x = $xVal;
$this->y = $yVal;
}
public function
getX() { return $this->x; }
public function
getY() { return $this->y; }
}

$p = new Point(25, 35);
echo
$p->getX(); // 25
echo $p->getY(); // 35
?>
Ok, now we need extra powers. PHP gives us several options:
A. We can tag on extra properties on-the-fly using everyday PHP syntax...
$p->z = 45; // here, $p is still an object of type [Point] but gains no capability, and it's on a per-instance basis, blah.
B. We can try type-casting it to a different type to access more functions...
$p = (SuperDuperPoint) $p; // if this is even allowed, I doubt it. But even if PHP lets this slide, the small amount of data Point holds would probably not be enough for the extra functions to work anyway. And we still need the class def + all extra data. We should have just instantiated a [SuperDuperPoint] object to begin with... and just like above, this only works on a per-instance basis.
C. Do it the right way using OOP - and just extend the Point class already.
<?php
class Point3D extends Point {
protected
$z; // add extra properties...

public function __construct($xVal = 0, $yVal = 0, $zVal = 0) {
parent::__construct($xVal, $yVal);
$this->z = $zVal;
}
public function
getZ() { return $this->z; } // add extra functions...
}

$p3d = new Point3D(25, 35, 45); // more data, more functions, more everything...
echo $p3d->getX(); // 25
echo $p3d->getY(); // 35
echo $p3d->getZ(); // 45
?>
Once the new class definition is written, you can make as many Point3D objects as you want. Each of them will have more data and functions already built-in. This is much better than trying to beef-up any "single lesser object" on-the-fly, and it's way easier to do.
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-2
philip_snyder at hotmail dot com
20 years ago
Re: the typecasting between classes post below... fantastic, but slightly flawed. Any class name longer than 9 characters becomes a problem... SO here's a simple fix:

function typecast($old_object, $new_classname) {
if(class_exists($new_classname)) {
// Example serialized object segment
// O:5:"field":9:{s:5:... <--- Class: Field
$old_serialized_prefix = "O:".strlen(get_class($old_object));
$old_serialized_prefix .= ":\"".get_class($old_object)."\":";

$old_serialized_object = serialize($old_object);
$new_serialized_object = 'O:'.strlen($new_classname).':"'.$new_classname . '":';
$new_serialized_object .= substr($old_serialized_object,strlen($old_serialized_prefix));
return unserialize($new_serialized_object);
}
else
return false;
}

Thanks for the previous code. Set me in the right direction to solving my typecasting problem. ;)
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-2
Anonymous
18 years ago
If you have a boolean, performing increments on it won't do anything despite it being 1. This is a case where you have to use a cast.

<html>
<body> <!-- don't want w3.org to get mad... -->
<?php
$bar
= TRUE;
?>
I have <?=$bar?> bar.
<?php
$bar
++;
?>
I now have <?=$bar?> bar.
<?php
$bar
= (int) $bar;
$bar++;
?>
I finally have <?=$bar?> bar.
</body>
</html>

That will print

I have 1 bar.
I now have 1 bar.
I finally have 2 bar.
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-4
Anonymous
13 years ago
Checking for strings to be integers?
How about if a string is a float?

<?php

/* checks if a string is an integer with possible whitespace before and/or after, and also isolates the integer */
$isInt=preg_match('/^\s*([0-9]+)\s*$/', $myString, $myInt);

echo
'Is Integer? ', ($isInt) ? 'Yes: '.$myInt[1] : 'No', "\n";

/* checks if a string is an integer with no whitespace before or after */
$isInt=preg_match('/^[0-9]+$/', $myString);

echo
'Is Integer? ', ($isInt) ? 'Yes' : 'No', "\n";

/* When checking for floats, we assume the possibility of no decimals needed. If you MUST require decimals (forcing the user to type 7.0 for example) replace the sequence:
[0-9]+(\.[0-9]+)?
with
[0-9]+\.[0-9]+
*/

/* checks if a string is a float with possible whitespace before and/or after, and also isolates the number */
$isFloat=preg_match('/^\s*([0-9]+(\.[0-9]+)?)\s*$/', $myString, $myNum);

echo
'Is Number? ', ($isFloat) ? 'Yes: '.$myNum[1] : 'No', "\n";

/* checks if a string is a float with no whitespace before or after */
$isInt=preg_match('/^[0-9]+(\.[0-9]+)?$/', $myString);

echo
'Is Number? ', ($isFloat) ? 'Yes' : 'No', "\n";

?>
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-3
alexgr at gmail dot com
15 years ago
For a Cast to a User Defined Object you can define a cast method:

class MyObject {
/**
* @param MyObject $object
* @return MyObject
*/
static public function cast(MyObject $object) {
return $object;
}
}

In your php page code you can:
$myObject = MyObject::cast($_SESSION["myObject"]);

Then, PHP will validate the value and your IDE will help you.
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-4
mbrowne83 (at GM)
9 years ago
The code listed in some of the comments here for supposedly "casting" from one class to another using unserialize/serialize does not actually change the class of the existing object; it creates a new object. So it's not the same as a cast.
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-4
Eric Lavoie
9 years ago
(array) null
array(null)

are not the same.

var_dump((array) null) =>
array (size=0)
empty

var_dump(array (null)) =>
array (size=1)
0 => null
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-3
post_at_henribeige_dot_de
20 years ago
If you want to do not only typecasting between basic data types but between classes, try this function. It converts any class into another. All variables that equal name in both classes will be copied.

function typecast($old_object, $new_classname) {
if(class_exists($new_classname)) {
$old_serialized_object = serialize($old_object);
$new_serialized_object = 'O:' . strlen($new_classname) . ':"' . $new_classname . '":' .
substr($old_serialized_object, $old_serialized_object[2] + 7);
return unserialize($new_serialized_object);
}
else
return false;
}

Example:

class A {
var $secret;
function A($secret) {$this->secret = $secret;}
function output() {echo("Secret class A: " . $this->secret);}
}

class B extends A {
var $secret;
function output() {echo("Secret class B: " . strrev($this->secret));}
}

$a = new A("Paranoia");
$b = typecast($a, "B");

$a->output();
$b->output();
echo("Classname \$a: " . get_class($a) . "Classname \$b: " . get_class($b));

Output of the example code above:

Secret class A: Paranoia
Secret class B: aionaraP
Classname $a: a
Classname $b: b
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-3
dimo dot vanchev at bianor dot com
20 years ago
For some reason the code-fix posted by philip_snyder at hotmail dot com [27-Feb-2004 02:08]
didn't work for me neither with long_class_names nor with short_class_names. I'm using PHP v4.3.5 for Linux.
Anyway here's what I wrote to solve the long_named_classes problem:

<?php
function typecast($old_object, $new_classname) {
if(
class_exists($new_classname)) {
$old_serialized_object = serialize($old_object);
$old_object_name_length = strlen(get_class($old_object));
$subtring_offset = $old_object_name_length + strlen($old_object_name_length) + 6;
$new_serialized_object = 'O:' . strlen($new_classname) . ':"' . $new_classname . '":';
$new_serialized_object .= substr($old_serialized_object, $subtring_offset);
return
unserialize($new_serialized_object);
} else {
return
false;
}
}
?>
up
-4
tom5025_ at hotmail dot com
19 years ago
function strhex($string)
{
$hex="";
for ($i=0;$i<strlen($string);$i++)
$hex.=dechex(ord($string[$i]));
return $hex;
}
function hexstr($hex)
{
$string="";
for ($i=0;$i<strlen($hex)-1;$i+=2)
$string.=chr(hexdec($hex[$i].$hex[$i+1]));
return $string;
}

to convert hex to str and vice versa
up
-7
nullhilty at gmail dot com
15 years ago
Just a little experiment on the (unset) type cast:

<?php
$var
= 1;
$var_unset = (unset) $var;
$var_ref_unset &= (unset) $var;
var_dump($var);
var_dump($var_unset);
var_dump($var_ref_unset);
?>

output:
int(1)
NULL
int(0)
up
-8
davaakhuu at outlook dot com
8 years ago
Type Juggling<br/>
<?php $count = "2 cats"; ?>
Type: <?php echo gettype($count); ?><br/>
<?php $count += 3; ?>
Type: <?php echo gettype($count); ?><br/>
<?php $cats = "I have " . $count . "cats."; ?>
Cats: <?php echo gettype($cats); ?><br/>
<br/>
Type Casting<br/>
<?php settype($count, "integer"); ?>
count: <?php echo gettype($count); ?><br/>

<?php $count2 = (string)$count; ?>
count: <?php echo gettype($count); ?><br/>
count2: <?php echo gettype($count2); ?><br/>

<?php $test1 = 3; ?>
<?php $test2 = 3; ?>
<?php settype($test1, "string"); ?>
<?php (string)$test2; ?>
test1: <?php echo gettype($test1); ?><br/>
test2: <?php echo gettype($test2); ?><br/>
up
-9
kajsunansis at that gmail
15 years ago
json_decode users consider this, when casting stdClass to array:
<?php
$obj
= new stdClass();
$obj->{"2"} = "id";
$arr = (array) $obj;
$result = isset($arr["2"]) || array_key_exists(2, $arr); // false
?>
..though casting is at least 2x faster than foreach.
up
-18
Jeffrey
15 years ago
IMAGINATION REQUIRED...

We can be a witness to PHP's 'type-jugglin' in real-time with a simple implementation of a MemoryMap. For the sake our purposes, pretend that this is an empty MemoryMap.
+-------+------+------+-------+
| index | $var | type | value |
+-------+------+------+-------+
| 1 | --- | NULL | null |
| 2 | --- | NULL | null |
| 3 | --- | NULL | null |
| 4 | --- | NULL | null |
+-------+------+------+-------+

<?php
# create some variables...
$a = 10;
$b = "Hello";
$c = array(55.45, 98.65);
# Now look at map...
?>
+-------+-------+---------+--------+
| index | $var | type | value |
+-------+-------+---------+--------+
| 1 | $a | INTEGER | 10 |
| 2 | $b | STRING | Hello |
| 3 | $c[0] | FLOAT | 55.45 |
| 4 | $c[1] | FLOAT | 98.65 |
+-------+-------+---------+--------+
<?php
# Now, change the variable types...
$a = "Bye";
$b = 2;
$c[0] = "Buy";
$c[1] = "Now!";
#Look at map...
?>
+-------+-------+---------+--------+
| index | $var | type | value |
+-------+-------+---------+--------+
| 1 | $a | STRING | Bye | <- used to be INTEGER
| 2 | $b | INTEGER | 2 | <- used to be STRING
| 3 | $c[0] | STRING | Buy | <- used to be FLOAT
| 4 | $c[1] | STRING | Right | <- used to be FLOAT
+-------+-------+---------+--------+
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