Set type int php

Cast a string to binary using PHP < 5.2.1

I found it tricky to check if a posted value was an integer.

is_int ( $_POST [ ‘a’ ] ); //false
is_int ( intval ( «anything» ) ); //always true
?>

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

$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
?>

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:

$hello = ‘Hello world’ ;
print $hello ;
unset( $hello );

$hello = ‘Hello world’ ;
$hello = (unset) print $hello ;

Hoorah, we lost another line!

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!

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’ $v=(array) $u; // array 0 => string ‘abc’

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:

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.

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:

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.
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.
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.

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: $old_serialized_prefix = «O:».strlen(get_class($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. 😉

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.

I have 1 bar.
I now have 1 bar.
I finally have 2 bar.

Checking for strings to be integers?
How about if a string is a float?

/* checks if a string is an integer with possible whitespace before and/or after, and also isolates the integer */
$isInt = preg_match ( ‘/^\s*(6+)\s*$/’ , $myString , $myInt );

echo ‘Is Integer? ‘ , ( $isInt ) ? ‘Yes: ‘ . $myInt [ 1 ] : ‘No’ , «\n» ;

/* checks if a string is an integer with no whitespace before or after */
$isInt = preg_match ( ‘/^2+$/’ , $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:
3+(\.9+)?
with
8+\.5+
*/

/* checks if a string is a float with possible whitespace before and/or after, and also isolates the number */
$isFloat = preg_match ( ‘/^\s*(5+(\.6+)?)\s*$/’ , $myString , $myNum );

echo ‘Is Number? ‘ , ( $isFloat ) ? ‘Yes: ‘ . $myNum [ 1 ] : ‘No’ , «\n» ;

/* checks if a string is a float with no whitespace before or after */
$isInt = preg_match ( ‘/^3+(\.4+)?$/’ , $myString );

echo ‘Is Number? ‘ , ( $isFloat ) ? ‘Yes’ : ‘No’ , «\n» ;

Источник

settype

Возвращает true в случае успешного выполнения или false в случае возникновения ошибки.

Примеры

Пример #1 Пример использования settype()

$foo = «5bar» ; // строка
$bar = true ; // булевое значение

settype ( $foo , «integer» ); // $foo теперь 5 (целое)
settype ( $bar , «string» ); // $bar теперь «1» (строка)
?>

Примечания

Замечание:

Максимальное значение для «int» равно PHP_INT_MAX .

Смотрите также

User Contributed Notes 17 notes

Note that you can’t use this to convert a string ‘true’ or ‘false’ to a boolean variable true or false as a string ‘false’ is a boolean true. The empty string would be false instead.

$var = «true» ;
settype ( $var , ‘bool’ );
var_dump ( $var ); // true

$var = «false» ;
settype ( $var , ‘bool’ );
var_dump ( $var ); // true as well!

$var = «» ;
settype ( $var , ‘bool’ );
var_dump ( $var ); // false
?>

Just a quick note, as this caught me out very briefly:

settype() returns bool, not the typecasted variable — so:

$blah = settype($blah, «int»); // is wrong, changes $blah to 0 or 1
settype($blah, «int»); // is correct

Hope this helps someone else who makes a mistake.. 😉

Using settype is not the best way to convert a string into an integer, since it will strip the string wherever the first non-numeric character begins. The function intval($string) does the same thing.

If you’re looking for a security check, or to strip non-numeric characters (such as cleaning up phone numbers or ZIP codes), try this instead:

you must note that this function will not set the type permanently! the next time you set the value of that variable php will change its type as well.

/*
This example works 4x faster than settype() function in PHP-CGI 5.4.13 and
8x faster in PHP-CGI 7.1.3(x64) for windows
*/

If you attempt to convert the special $this variable from an instance method (only in classes) :
* PHP will silently return TRUE and leave $this unchanged if the type was ‘bool’, ‘array’, ‘object’ or ‘NULL’
* PHP will generate an E_NOTICE if the type was ‘int’, ‘float’ or ‘double’, and $this will not be casted
* PHP will throw a catchable fatal error when the type is ‘string’ and the class does not define the __toString() method
Unless the new variable type passed as the second argument is invalid, settype() will return TRUE. In all cases the object will remain unchanged.
// This was tested with PHP 7.2
class Foo function test () printf ( «%-20s %-20s %s\n» , ‘Type’ , ‘Succeed?’ , ‘Converted’ );

// settype() should throw a fatal error, as $this cannot be re-assigned
printf ( «%-20s %-20s %s\n» , ‘bool’ , settype ( $this , ‘bool’ ), print_r ( $this , TRUE ));
printf ( «%-20s %-20s %s\n» , ‘int’ , settype ( $this , ‘int’ ), print_r ( $this , TRUE ));
printf ( «%-20s %-20s %s\n» , ‘float’ , settype ( $this , ‘float’ ), print_r ( $this ));
printf ( «%-20s %-20s %s\n» , ‘array’ , settype ( $this , ‘array’ ), print_r ( $this , TRUE ));
printf ( «%-20s %-20s %s\n» , ‘object’ , settype ( $this , ‘object’ ), print_r ( $this , TRUE ));
printf ( «%-20s %-20s %s\n» , ‘unknowntype’ , settype ( $this , ‘unknowntype’ ), print_r ( $this , TRUE ));
printf ( «%-20s %-20s %s\n» , ‘NULL’ , settype ( $this , ‘NULL’ ), print_r ( $this , TRUE ));
printf ( «%-20s %-20s %s\n» , ‘string’ , settype ( $this , ‘string’ ), print_r ( $this , TRUE ));
>
>
$a = new Foo ();
$a -> test ();
?>
Here is the result :
Type Succeed? Converted
bool 1 Foo Object
(
)

Notice: Object of class Foo could not be converted to int in C:\php\examples\oop-settype-this.php on line 9

Notice: Object of class Foo could not be converted to float in C:\php\examples\oop-settype-this.php on line 10

Warning: settype(): Invalid type in C:\php\examples\oop-settype-this.php on line 14

Catchable fatal error: Object of class Foo could not be converted to string in C:\php\examples\oop-settype-this.php on line 15

If the class Foo implements __toString() :
class Foo // .
function __toString () return ‘Foo object is awesome!’ ;
>
// .
>
?>
So the first code snippet will not generate an E_RECOVERABLE_ERROR, but instead print the same string as for the other types, and not look at the one returned by the __toString() method.

Источник

Преобразовать строку в число (PHP)

В PHP преобразовать строку в число в PHP можно тремя способами. Функцией bool settype (mixed &var, string type) , функцией int intval(mixed var [,int base]) или приведением к типу — (int) или (integer) .

Пример

Например есть строка «123» нужно преобразовать ее в тип integer .

Приведение к типу (int)

settype()

intval()

Быстродействие

В плане быстродействия самым быстрым оказался первый способ (приведение к типу — (int)$str ), номером 2 оказался способ settype() и самым медленным оказался способ intval() .

Скорость измерялась обычным способом, строка «123» 1 миллион раз преобразовывалась в тип int .

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Источник

Set type int php

Set type int php

settype

Примеры

Примечания

Смотрите также

User Contributed Notes 17 notes

Преобразовать строку в число (PHP)

Пример

Приведение к типу (int)

settype()

intval()

Быстродействие

Категории

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