PHP dynamic get function parameter steps

This time to bring you the PHP dynamic access to function parameters of the steps in detail, PHP dynamic access to the function parameters of the note, the following is the actual case, together to see.

PHP supports a variable number of parameter lists in user-defined functions. In fact, it's 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 in are:
Array (size=3)
0 = String ' a ' (length=1)
1 = string ' B ' (length=1)
2 = String ' C ' (length=1)

3. func_get_arg-returns 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

Number of parameters: 3
The second parameter is: b

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