(PHP 4, PHP 5, PHP 7, PHP 8)
settype — Set the type of a variable
varThe variable being converted.
type
Possibles values of type are:
Приклад #1 settype() example
<?php
$foo = "5bar"; // string
$bar = true; // boolean
settype($foo, "integer"); // $foo is now 5 (integer)
settype($bar, "string"); // $bar is now "1" (string)
?>Зауваження:
Maximum value for "int" is
PHP_INT_MAX.
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...
<?php
$var = "true";
settype($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.. ;)<?php
/*
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
*/
$v = '12345';
$v = (int)$v;
$v = (string)$v;
?>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:
<?
$number=ereg_replace("[^0-9]","",$number);
?>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.Please note:
When using settype to convert indexed arrays to objects, the properties of the typed object will be integers:
A brief example:
$a = ['1', '2'];
settype($a, 'object');
var_dump($a);
// output
object(stdClass)#1 (2) {
["0"]=>
string(1) "1"
["1"]=>
string(1) "2"
}using (int) insted of the settype function works out much better for me. I have always used it. I personally don't see where settype would ever come in handy.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.
<?php
// 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
int 1 Foo Object
(
)
Notice: Object of class Foo could not be converted to float in C:\php\examples\oop-settype-this.php on line 10
float 1 Foo Object
(
)
array 1 Foo Object
(
)
object 1 Foo Object
(
)
Warning: settype(): Invalid type in C:\php\examples\oop-settype-this.php on line 14
unknowntype Foo Object
(
)
NULL 1 Foo Object
(
)
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() :
<?php
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.
Hope this helps ! :)This settype() behaviour seems consistent to me. Quoting two sections from the manual:
"When casting from a scalar or a string variable to an array, the variable will become the first element of the array: "
<pre>
2 $var = 'ciao';
3 $arr = (array) $var;
4 echo $arr[0]; // outputs 'ciao'
</pre>
And if (like your code above) you do a settype on an empty variable, you'll end up with a one element array with an empty (not unset!) first element. So appeanding to it will start appending at index 1. As for why reset() doesn't do anything:
"When you assign a value to an array variable using empty brackets, the value will be added onto the end of the array."
It doesn't matter where the array counter is; values are added at the end, not at the counter.