<?php
function xt_sum($a, $b)
{
return $a + $b;
}
echo xt_sum(4, 5), "\n";
//可变参数
function sum(...$numbers)
{
$acc = 0;
foreach ($numbers as $n) {
$acc += $n;
}
return $acc;
}
echo sum(1, 2, 3, 4) . "\n";
//数组解包
echo sum(...[1, 2, 3, 4, 5]) . "\n";
//默认参数
function makecoffee($type = "cappuccino")
{
return "Making a cup of {$type}.\n";
}
echo makecoffee();
echo makecoffee(null);
echo makecoffee("espresso");
<?php
function makecoffee($types = array("cappuccino"), $coffeeMaker = NULL)
{
$device = is_null($coffeeMaker) ? "hands" : $coffeeMaker;
return "Making a cup of " . join(", ", $types) . " with {$device}.\n";
}
echo makecoffee();
echo makecoffee(array("cappuccino", "lavazza"), "teapot");
return "Making a cup of $type.\n";
}
echo makecoffee(); //Making a cup of cappuccino.
echo makecoffee(null); //Making a cup of .
echo makecoffee("espresso"); //Making a cup of espresso.
?>
<?php
#Example #4 Using non-scalar types as default values
function makecoffee($types = array("cappuccino"), $coffeeMaker = NULL)
{
$device = is_null($coffeeMaker) ? "hands" : $coffeeMaker;
return "Making a cup of ".join(", ", $types)." with $device.\n";
}
echo makecoffee(); //Making a cup of cappuccino with hands
echo makecoffee(array("cappuccinoooo", "lavazza"), "teapot"); // Making a cup of cappuccinoooo,
// lavazza with teapot
?>
<?php
#Example #5 Incorrect usage of default function arguments
function makeyogurt($type = "acidophilus", $flavour)
{
return "Making a bowl of $type $flavour.\n";
}
echo makeyogurt("raspberry"); // won't work as expected --Warning: Missing argument 2 for makeyogurt(), called in
//Notice: Undefined variable: flavour in
//Making a bowl of raspberry.
?>
<?php
<?php
#Example #3 Use of default parameters in functions
function makecoffee($type = "cappuccino")
{
return "Making a cup of $type.\n";
}
echo makecoffee(); //Making a cup of cappuccino.
echo makecoffee(null); //Making a cup of .
echo makecoffee("espresso"); //Making a cup of espresso.
?>
echo makecoffee1();
echo makecoffee1(null);
echo makecoffee1("xudedong"), "<BR>";
?>
<!--PHP 还允许使用数组 array 和特殊类型 NULL 作为默认参数，使用非标量类型作为默认参数,
默认值必须是常量表达式，不能是诸如变量，类成员，或者函数调用等。-->
<?php
function makecoffee($types = array("aaaaa"), $coffeeMaker = NULL)
{
$device = is_null($coffeeMaker) ? "null" : "hands,{$coffeeMaker}";
return "Making a cup of " . join(",", $types) . " with {$device}.\n";
}
echo makecoffee(), "<BR>";
echo 1.111111111111111E+27, "<BR>";
echo makecoffee(array("aaaaa", "bbbbb", "ccc"), 'ttt');
?>
<!--注意当使用默认参数时，任何默认参数必须放在任何非默认参数的右侧；否则，函数将不会按照预期的情况工作。-->
<!--函数默认参数的不正确用法-->
<?php
function makeyogurt($type = "access", $flavour)
{
return "Making a bowl of {$type}+++++++++++++++++++ {$flavour}.\n";
}
echo makeyogurt("dddddddddd"), "<BR>";
?>
<!--函数默认参数的正确用法-->
<?php
<?php
define("BR", "</br>");
function add_some_extra(&$string)
{
$string .= 'и кое-что еще.';
}
$str = 'Это строка, ';
add_some_extra($str);
echo $str;
// выведет 'Это строка, и кое-что еще.'
echo BR;
function makecoffee1($type = "капуччино")
{
return "Готовим чашку {$type}.\n";
}
echo makecoffee1();
echo makecoffee1(null);
echo makecoffee1("эспрессо");
echo BR;
function makecoffee($types = array("капуччино"), $coffeeMaker = NULL)
{
$device = is_null($coffeeMaker) ? "вручную" : $coffeeMaker;
return "Готовлю чашку " . join(", ", $types) . " {$device}.\n";
}
echo makecoffee();
echo makecoffee(array("капуччино", "лавацца"), "в чайнике");
