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
?>
PHP - Manual: settype
2024-11-23
settype
(PHP 4, PHP 5, PHP 7, PHP 8)
settype — 设置变量的类型
参数
-
var -
要转换的变量。
-
type -
type的可能值为：- “boolean” （或为“bool”，从 PHP 4.2.0 起）
- “integer” （或为“int”，从 PHP 4.2.0 起）
- “float” （只在 PHP 4.2.0 之后可以使用，对于旧版本中使用的“double”现已停用）
- "string"
- "array"
- "object"
- “null” （从 PHP 4.2.0 起）
返回值
成功时返回 true， 或者在失败时返回 false。
范例
示例 #1 settype() 示例
<?php
$foo = "5bar"; // string
$bar = true; // boolean
settype($foo, "integer"); // $foo 现在是 5 (integer)
settype($bar, "string"); // $bar 现在是 "1" (string)
?>
注释
注意:
Maximum value for "int" is
PHP_INT_MAX.
add a note
User Contributed Notes 17 notes
Special Notes ¶
10 years ago
robin at barafranca dot com ¶
14 years ago
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.. ;)
sdibb at myway dot com ¶
18 years ago
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);
?>
nospamplease at veganismus dot ch ¶
16 years ago
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.
Anonymous ¶
3 years ago
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 ! :)
DarkMaster ¶
1 year ago
<?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;
?>
matt at mattsoft dot net ¶
16 years ago
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.
geoffsmiths at hotmail dot com ¶
2 years ago
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"
}
Skayo ¶
4 years ago
$foo = "1";
settype($foo, "bool");
var_dump($foo); // Outputs: bool(true)
$bar = "0";
settype($bar, "bool");
var_dump($bar); // Outputs: bool(false)
reinier_deblois at hotmail dot com ¶
17 years ago
Instead of settype you could use:
<?php
$int=593; // $int is a integer
$int.=""; // $int is now a string
ludvig dot ericson gmail.dot com ¶
16 years ago
To matt:
This function accepts a paremeter, which does not imply you using hardcoded stuff, instead you can let the user choose! \o/
As a part of a framework or something.
Plus, you can probably call this with call_user_func
ns at canada dot com ¶
22 years ago
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 $arr[0]; // outputs 'ciao'
</pre>
And if (like your code above) you do a settype on an empty variable, you'll end up with a one element array with an empty (not unset!) first element. So appeanding to it will start appending at index 1. As for why reset() doesn't do anything:
"When you assign a value to an array variable using empty brackets, the value will be added onto the end of the array."
It doesn't matter where the array counter is; values are added at the end, not at the counter.
NWdev ¶
13 years ago
In trying to convert an array of strings to an array of ints,
I attempted to use settype with array_walk.
<?php
//$numArray is generated by another process
$numArray = array('13','14','33');
var_dump($numArray);
//my conversion function
function str_to_int($val){
//remember: settype($x, 'int') returns boolean (1=success, 0=failure)
//--> so return $x to return new value
settype($val,'int');
echo "<br />gettype = ".gettype($val)."<br />";
return $val;
}
array_walk($numArray,'str_to_int');
var_dump($numArray);
?>
The var_dumps both return the following:
<?php
array(3) { [0]=> string(2) "13" [1]=> string(2) "14" [2]=> string(2) "33" }
?>
The gettype echo will show the value as an integer.
So it seems that settype($val,'int') makes the conversion,
but the function return value remains a string.
Since settype returns a boolean, using
<?php $val = settype($val, 'int'); ?>
is not a option.
I resolved my array value conversion using this instead:
<?php
$numArray =
array_map(create_function('$value', 'return (int)$value;'),$numArray);
?>
Thanks to the posting here:
http://usrportage.de/archives/
808-Convert-an-array-of-strings-into-an-array-of-integers.html
Perhaps this will save someone else spinning wheels a bit.
Also thanks to robin at barafranca dot com for
pointing out the boolean return value of settype.
memandeemail at gmail dot com ¶
17 years ago
/**
* @return bool
* @param array[byreference] $values
* @desc Convert an array or any value to Escalar Object [not tested in large scale]
*/
function setobject(&$values) {
$values = (object) $values;
foreach ($values as $tkey => $val) {
if (is_array($val)) {
setobject($val);
$values->$tkey = $val;
}
}
return (bool) $values;
}
Michael Benedict ¶
16 years ago
note that settype() will initialize an undefined variable. Therefore, if you want to preserve type and value, you should wrap the settype() call in a call to isset().
<?php
settype($foo, "integer");
echo("|$foo|");
?>
prints "|0|", NOT "||".
To get the latter, use:
<?php
if(isset($foo)) settype($foo, "integer");
echo("|$foo|");
?>
marjune ¶
5 years ago
any digit except 0 or -0 are considered true in boolean, and any string except '0' or '' are also considered true.
<?php
$foo = '0';
settype($foo, 'boolean');
var_dump($foo); // false
$foo = 0;
settype($foo, 'boolean');
var_dump($foo); // false
Chris Sullins ¶
12 years ago
settype() has some really strange, potentially buggy behavior.
As noted by Michael Benedict, using settype() on a variable will initialize that variable. What is stranger is that using settype() on an uninitialized variable that you are treating as an array or object will also initialize the variable. So:
<?php
settype($foo->bar,"integer"); // stdClass Object ( [test] => 0 )
?>
This works for a chain of any length: $foo->bar['baz']->etc
Next we look at what happens if $foo is already set.
<?php
$foo = false;
settype($foo->bar,"integer"); // stdClass Object ( [test] => 0 )
?>
In and of itself, this wouldn't be problematic. It might even make sense. But in all other cases where $foo is defined, even if (boolean) $foo === false, it will throw an error unless $foo->bar is valid (i.e. $foo is an object already).
<?php
$foo = true;
settype($foo->bar,"integer"); // Notice: Trying to get property of non-object
?>
IT
PHP
编程语言
Linux
开发编程
科技
Elasticsearch
HTML/CSS/XML
网络
JAVA
NoSQL
数据库
面试
C/C++
Golang
Git
算法
操作系统
正则表达式
Redis
互联网
MySql
JavaScript
运维
软件
国际
架构设计
Mac OS
TCP/IP
Excel
Vim
Windows
Socket
Oracle
VR
MongoDB
Python
运营
MemCache
商业
硬件
电子
娱乐
设计
nginx
摄影
游戏
WordPress
HTTP
团建
数码电器
广告
--
php7 安装fileinfo扩展
preg_split — 通过一个正则表达式分隔字符串
php位值,解决 PHP 中 usort 在值相同时改变原始位置的问题
[PHP] inet_pton/inet_ntop IP地址转换函数
array_multisort() 多字段排序
PHPMailer设置utf8 PHPMailer字符集CharSet
ADORecordSet对象
PHP 8.1
[鸟哥]PHP_INT_MIN 和 -9223372036854775808
adodb手册
opcache预加载
Composer的Packagist资源
mysql面试题
php中几种注释规范
[原创]诡异的php-fpm超时问题
php扩展开发
PHP7 mcrypt替代方案
laravel框架查看sql语句方式
Packagist / Composer 中国全量镜像
支持php7的性能采集扩展