gettype

描述

string gettype ( mixed var )

返回 PHP 变量的类型 var.

警告

不要使用 gettype() 来测试某种类型，因为其返回的字符串在未来的版本中可能需要改变。此外，由于包含了字符串的比较，它的运行也是较慢的。

使用 is_* 函数代替。

返回的字符串的可能值为：

“boolean”（从 PHP 4 起）
“integer”
“double”（由于历史原因，如果是 float 则返回“double”，而不是“float”）
“string”
“array”
“object”
“resource”（从 PHP 4 起）
“NULL”（从 PHP 4 起）
“user function”（只用于 PHP 3，现已停用）
“unknown type”

对于 PHP 4，你应该使用 function_exists() 和 method_exists() 取代先前将 gettype() 作用于函数的用法。

参见 settype()、is_array()、is_bool()、is_float()、is_integer()、is_null()、is_numeric()、is_object()、is_resource()、is_scalar() 和 is_string()。

add a note User Contributed Notes

gilthansNOSPAM at gmail dot com
12-Sep-2005 04:18


NaN and #IND will return double or float on gettype, while some inexistent values, like division by zero, will return as a boolean FALSE. 0 by the 0th potency returns 1, even though it is mathematically indetermined.



<?php

$number = 5/0;

$number2 = sqrt(-3);

$number3 = pow(0, 0);

$number4 = 0/0;



echo $number."<br />";

echo $number2."<br />";

echo $number3."<br />";

echo $number4."<br />";

echo "<br />";

echo gettype($number)."<br />";

echo gettype($number2)."<br />";

echo gettype($number3)."<br />";

echo gettype($number4);

?>



This will return:



-1.#IND

1



boolean

double

integer

boolean



0

1

1

0

PHP Warning: Division by zero in C\test.php on line 2 PHP Warning: Division by zero in C:\test.php on line 5

matt at appstate
17-Dec-2004 03:10


Here is something that had me stumped with regards to gettype and is_object.

Gettype will report an incomplete object as such, whereas is_object will return FALSE.



if (!is_object($incomplete_obj)) {

   echo 'This variable is not an object, it is a/an ' . gettype($incomplete_obj);

}



Will print:

This variable is not an object, it is a/an object

jose at vocis dot com
15-Sep-2000 12:22


Also returns "NULL" for variables assigned the return of a function that returned no value via "return;". 





<code>





function weird(){


    return;


}


$a=weird();





</code>





isset($a) <> 1


empty($a) <> 1


gettype($a) == NULL





-Jose Batista

ojones at dotclick dot com
01-Sep-2000 01:19


After calling OCIResult to retrieve a NULL result from an Oracle result-set, gettype returns the string 'NULL'.

add a note