How PHP dynamically obtains function parameter instance code

PHP in the userCustom functions A variable number of parameter lists are supported in the It's really simple, just use Func_num_args () , Func_get_arg () , and Func_get_args () function.

mutable parameters do not require special syntax, and parameter lists are still passed to the function as defined by the function and are used in the usual way.

1.func_num_args -Returns the total number of arguments passed in the function

int Func_num_args (void)

Example

<?phpfunction  Demo () {    $numargs  =  Func_num_args ();    echo  "Number of parameters:  $numargs \ n";} Demo (' A ',  ' B ',  ' C '); >

Run results

Number of parameters: 3

2.func_get_args-returns the argument list of the passed-in function

Array Func_get_args  (void)

Example

<?phpfunction  Demo () {    $args = Func_get_args ();    echo "Incoming parameters are:";    Var_dump ($args);} Demo (' A ',  ' B ',  ' C '); >

Run results

The parameters passed are: Array (size=3)  0 = = String ' A ' (length=1)  1 = string ' B ' (length=1)  2 = = String ' C ' (len gth=1)

3.func_get_arg-returning parameter values from the parameter list based on the parameter index

Mixed  func_get_arg  (int $arg _num  )

Example

<?phpfunction  Demo () {    $numargs  =  Func_num_args ();    echo  "Number of parameters:  $numargs <br/>";    $args = Func_get_args ();    if ($numargs  >=  2) {        echo  "The second parameter is:"  .  Func_get_arg (1).  " <br/> ";    }} Demo (' A ',  ' B ',  ' C '); >

Run results

The number of parameters is: 3 The second parameter is: b