PHP functions use a variable number of parameters

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PHP supports a variable number of parameter lists in user-defined functions.

In php5.5 and earlier versions, the Func_num_args (), Func_get_arg ( ), and Func_get_args () functions were implemented.

<?phpfunction MyFunc () {    //Get the number of parameters    echo Func_num_args (). Php_eol;    Gets the value of the first parameter:    print_r (func_get_arg (0));    echo Php_eol;    Gets the value of all parameters    Print_r (Func_get_args ());    echo Php_eol;} MyFunc (' a '); MyFunc (1, 2, 3); MyFunc (Array (' d ', ' e '), array (' F '));? >

Output:

1aArray (    [0] = a) 31Array (    [0] = 1    [1] = 2    [2] + 3) 2Array (    [0] + D    [1] =& Gt e) Array (    [0] = = Array        (            [0] = + d            [1] = e        )    [1]        = = Array (            [0] = > F        ))

In versions php5.6 and above, you can use ... Syntax implementation.

<?phpfunction myfunc (... $args) {    //Get the number of parameters    echo count ($args). Php_eol;    Gets the value of the first parameter:    print_r ($args [0]);    echo Php_eol;    Gets the value of all parameters    Print_r ($args);    echo Php_eol;} MyFunc (' a '); MyFunc (1, 2, 3); MyFunc (Array (' d ', ' e '), array (' F '));? >

Example 1: Using the ... $args instead of any number of parameters

The output is consistent with php5.5 using Func_num_args (), Func_get_arg (), and the Func_get_args () function.

<?phpfunction Add ($a, $b) {    echo $a + $b;} $args = Array (1, 2); Add (... $args); Output 3?>

Example 2: Array to parameter list

<?phpfunction display ($name, $tag, ... $args) {    echo ' name: '. $name. Php_eol;    Echo ' tag: '. $tag. Php_eol;    echo ' args: '. Php_eol;    Print_r ($args);    echo Php_eol;} Display (' Fdipzone ', ' Programmer ');d isplay (' Terry ', ' Designer ', 1, 2);d isplay (' Aoao ', ' tester ', Array (' A ', ' B '), Array ( ' C '), Array (' d '));? >

Example 3: Partial parameter designation, variable number of other parameters

Output:

Name:fdipzonetag:programmerargs:Array () name:terrytag:designerargs:Array (    [0] = 1    [1] = 2) Name: Aoaotag:testerargs:Array (    [0] = = Array        (            [0] = a            [1] = b        )    [1] = = Array        ( C11/>[0] = c        )    [2] = =        Array            ([0] = d        ))