Example of method to dynamically obtain function parameters in PHP

This article describes the method of PHP to dynamically obtain function parameters. Share it for your reference, as follows:

PHP supports variable number of parameter lists in user-defined functions. It's actually very simple, just use itfunc_num_args() ， func_get_arg(),andfunc_get_args()function.

Variable parameters do not require special syntax, and the parameter list is still passed to the function as defined by the function, and these parameters are used in the usual way.

1. func_num_args — Returns the total number of parameters passed in function

int func_num_args ( void )

Example

<?php
function demo ()
{
  $numargs = func_num_args ();
  echo "The number of parameters is: $numargs \n" ;
}
demo ( 'a' , 'b' , 'c' );

Running results

The number of parameters is: 3

2. func_get_args — Returns the parameter list of the incoming function

array func_get_args  ( void )

Example

<?php
function demo ()
{
  $args = func_get_args();
  echo "The parameters passed in are:";
  var_dump($args);
}
demo ( 'a' , 'b' , 'c' );

Running 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 — Return parameter value from parameter list based on parameter index

mixed  func_get_arg  ( int $arg_num  )

Example

<?php
function demo ()
{
  $numargs = func_num_args ();
  echo "The number of parameters is: $numargs <br />" ;
  $args = func_get_args();
  if ( $numargs &gt;= 2 ) {
    echo "The second parameter is: " . func_get_arg ( 1 ) . "&lt;br /&gt;" ;
  }
}
demo ( 'a' , 'b' , 'c' );

Running results

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

For more information about PHP related content, please check out the topic of this site:Summary of common functions and techniques for php》、《Summary of usage of php strings》、《PHP data structure and algorithm tutorial》、《Summary of PHP Programming Algorithm"and"Complete collection of PHP array (Array) operation techniques》

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