PHP determines variable type

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##php Commonly used functions for judging variables include gettype(), is_array(), is_bool(), is_float(), is_integer(), is_null(), is_numeric(), is_object(), is_resource(), is_scalar() and is_string() .

The gettype() function returns the type of the variable, such as "boolean", "integer", "double" (the float type will return "double" instead of "float"), "string", "array" ", "object", "resource", "NULL" and "unknown type" and other values ​​indicate the variable type, such as:

$var = "coding";
echo gettype($var);//string

while other functions confirm a certain variable type and return true or false, for example:

$var1=321;
var_dump(is_numeric($var1));//bool(true)
$var2="123";
var_dump(is_numeric($var2));//bool(true)

Note: is_numeric() is used to determine whether the variable is a number or a numeric string

Attachment: type conversion

If you say gettype( ) is used to obtain the variable type, then settype() is obviously to set the variable type. Here are several type conversion methods:

1.settype($var,type) function conversion

$var='124das.21321';
settype($var,'int');//第二个参数指定转换类型，可以是int、float、bool、string、array和object
var_dump($var);//int 124

2. Target type specified conversion

(int)$var;//括号内指定转换类型，可以是int、float、bool、string、array和object

3. Three specific type function conversion

intval($var) , floatval($var) and strval($var)

$var = '121.212sdsa';
var_dump(floatval($var)); // float 121.212

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