PHP 变量处理函数

PHP 变量处理函数是 PHP 核心的一部分。无需安装即可使用这些功能。

Function	Description
boolval()	Returns the boolean value of a variable
debug_zval_dump()	Dumps a string representation of an internal zend value to output
doubleval()	Alias of floatval()
empty()	Checks whether a variable is empty
floatval()	Returns the float value of a variable
get_defined_vars()	Returns all defined variables, as an array
get_resource_type()	Returns the type of a resource
gettype()	Returns the type of a variable
intval()	Returns the integer value of a variable
is_array()	Checks whether a variable is an array
is_bool()	Checks whether a variable is a boolean
is_callable()	Checks whether the contents of a variable can be called as a function
is_countable()	Checks whether the contents of a variable is a countable value
is_double()	Alias of is_float()
is_float()	Checks whether a variable is of type float
is_int()	Checks whether a variable is of type integer
is_integer()	Alias of is_int()
is_iterable()	Checks whether the contents of a variable is an iterable value
is_long()	Alias of is_int()
is_null()	Checks whether a variable is NULL
is_numeric()	Checks whether a variable is a number or a numeric string
is_object()	Checks whether a variable is an object
is_real()	Alias of is_float()
is_resource()	Checks whether a variable is a resource
is_scalar()	Checks whether a variable is a scalar
is_string()	Checks whether a variable is of type string
isset()	Checks whether a variable is set (declared and not NULL)
print_r()	Prints the information about a variable in a human-readable way
serialize()	Converts a storable representation of a value
settype()	Converts a variable to a specific type
strval()	Returns the string value of a variable
unserialize()	Converts serialized data back into actual data
unset()	Unsets a variable
var_dump()	Dumps information about one or more variables
var_export()	Returns structured information (valid PHP code) about a variable