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How to use gettype() function to determine the type of variable in PHP?

Apr 13, 2019 am 10:44 AM
php Variable type

gettype()函数是PHP中的一个内置函数,用于获取变量的类型;它可用于检查现有变量的类型。下面本篇文章就来给大家介绍一下gettype()函数,希望对大家有所帮助。【视频教程推荐:PHP教程

How to use gettype() function to determine the type of variable in PHP?

基本语法

string gettype ( $var )
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参数:gettype()函数接受单个参数$va,表示需要检查其类型的变量的名称。

返回值:此函数会返回字符串类型的值。返回字符串的可能值为:

 ● boolean:表示变量为布尔类型

 ● integer:表示变量为整数类型

 ● double :表示变量为float类型(由于历史原因,如果为float类型,则返回“double”)。

 ● string:表示变量为string类型

 ● array:表示变量为数组类型

 ● object:表示变量为对象类型

 ● resource:表示变量为resource类型

 ● NULL:表示变量为NULL类型

 ● unknown type:未知类型

代码示例

下面我们通过代码示例来看看gettype()函数的使用。

示例1:

<?php 
  
$var1 = true; // 布尔值
$var2 = 3; // 整数值
$var3 = 5.6; // 浮点值
$var4 = "Abc3462"; // 字符串值
$var5 = array(1, 2, 3); // 数组值
$var6 = new stdClass; // 对象
$var7 = NULL; // null值
$var8 = tmpfile(); // resource值
  
echo gettype($var1)."<br>"; 
echo gettype($var2)."<br>"; 
echo gettype($var3)."<br>"; 
echo gettype($var4)."<br>"; 
echo gettype($var5)."<br>"; 
echo gettype($var6)."<br>"; 
echo gettype($var7)."<br>"; 
echo gettype($var8)."<br>"; 
  
?>
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输出:

boolean
integer
double
string
array
object
NULL
resource
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示例2:

<?php 
header("content-type:text/html;charset=utf-8");
$var1 = "php";  
$var2 = 10 % 7; 
$var3 = pow(10, 2); 
$var4 = pow(10, 0.5); 
$var5 =pow(-2,-3.2);
$var6 = sqrt(4); 
  
echo "变量\$var1=".$var1." ,类型为:".gettype($var1)."<br>"; 
echo "变量\$var2=".$var2." ,类型为:".gettype($var2)."<br>"; 
echo "变量\$var3=".$var3." ,类型为:".gettype($var3)."<br>"; 
echo "变量\$var4=".$var4." ,类型为:".gettype($var4)."<br>"; 
echo "变量\$var5=".$var5." ,类型为:".gettype($var5). "<br>"; 
echo "变量\$var6=".$var6." ,类型为:".gettype($var6); 
?>
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输出:

变量$var1=php ,类型为:string
变量$var2=3 ,类型为:integer
变量$var3=100 ,类型为:integer
变量$var4=3.1622776601684 ,类型为:double
变量$var5=NAN ,类型为:double
变量$var6=2 ,类型为:double
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说明:pow(x,y) 函数返回 x 的 y 次方,返回值是 Integer或Float类型;sqrt() 函数返回一个数的平方根,返回值为Float类型的。NAN(非数),是计算机科学中数值数据类型的一类值,表示未定义或不可表示的值。

以上就是本篇文章的全部内容,希望能对大家的学习有所帮助。更多精彩内容大家可以关注php中文网相关教程栏目!!!

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