How to get how many parameters a function has in php

php method to get several parameters of a function: 1. Return the total number of parameters passed to the function through the func_num_args function; 2. Return the parameter list of the passed function through the func_get_args function; 3. Return the parameter list from the function passed through the func_get_arg function. Parameter list returns the parameter value.

The operating environment of this article: windows7 system, PHP7.1 version, DELL G3 computer

How does php get the parameters of the function? ?

PHP method to dynamically obtain function parameters:

1. func_num_args - Returns the total number of parameters passed into the function

int func_num_args ( void )

Example

<?php
function demo ()
{
  $numargs = func_num_args ();
  echo "参数个数为: $numargs \n" ;
}
demo ( &#39;a&#39; , &#39;b&#39; , &#39;c&#39; );

Running result

The number of parameters is: 3

2. func_get_args — Returns the parameter list passed into the function

array func_get_args  ( void )

Example

<?php
function demo ()
{
  $args = func_get_args();
  echo "传入的参数分别为:";
  var_dump($args);
}
demo ( &#39;a&#39; , &#39;b&#39; , &#39;c&#39; );

Run result

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 according to parameter index

mixed  func_get_arg  ( int $arg_num  )

Example

<?php
function demo ()
{
  $numargs = func_num_args ();
  echo "参数个数为: $numargs <br />" ;
  $args = func_get_args();
  if ( $numargs >= 2 ) {
    echo "第二个参数为: " . func_get_arg ( 1 ) . "<br />" ;
  }
}
demo ( &#39;a&#39; , &#39;b&#39; , &#39;c&#39; );

Run result

The number of parameters is: 3

The second parameter is: b

Recommended learning: "PHP Video Tutorial"

The above is the detailed content of How to get how many parameters a function has in php. For more information, please follow other related articles on the PHP Chinese website!