php函数设定参数类型（php str_replace()函数的用法，有那些参数？）

我爱编程网小编给大家带来了php函数设定参数类型（php str_replace()函数的用法，有那些参数？）相关文章，一起来看一下吧。

本文目录一览：

• 1、php函数设定参数类型
• 2、php str_replace()函数的用法，有那些参数？
• 3、用PHP定义一个函数，返回3个参数中的最大值？

php函数设定参数类型

php 函数的参数类型可以指定为类名或数组类型array，比如
这样是对的public function Right( My_Class $a, array $b )
这样是错的public function Wrong( string $a, boolean $b )

如果需要其他类型，需要在函数内部进行类型检查
参考

这一段
public function Right( My_Class $a, array $b )

tells first argument have to by object of My_Class, second an array. My_Class means that you can pass also object of class that either extends My_Class or implements (if My_Class is abstract class) My_Class. If you need exactly My_Class you need to either make it final, or add some code to check what $a really.

Also note, that (unfortunately) "array" is the only built-in type you can use in signature. Any other types i.e.:

public function Wrong( string $a, boolean $b )

will cause an error, because PHP will complain that $a is not an *object* of class string (and $b is not an object of class boolean).

So if you need to know if $a is a string or $b bool, you need to write some code in your function body and i.e. throw exception if you detect type mismatch (or you can try to cast if it's doable).

我爱编程网

php str_replace()函数的用法，有那些参数？

请下载PHP参考手册CHM版，里边有详细的说明，先摘录如下
str_replace
(PHP 4, PHP 5)

str_replace — Replace all occurrences of the search string with the replacement string

说明
mixed str_replace ( mixed $search, mixed $replace, mixed $subject [, int &$count] )

This function returns a string or an array with all occurrences of search in subject replaced with the given replace value.

If you don't need fancy replacing rules (like regular expressions), you should always use this function instead of ereg_replace() or preg_replace().

参数
If search and replace are arrays, then str_replace() takes a value from each array and uses them to do search and replace on subject. If replace has fewer values than search, then an empty string is used for the rest of replacement values. If search is an array and replace is a string, then this replacement string is used for every value of search. The converse would not make sense, though.

If search or replace are arrays, their elements are processed first to last.

search

replace

subject
If subject is an array, then the search and replace is performed with every entry of subject, and the return value is an array as well.

count
注意: If passed, this will hold the number of matched and replaced needles.

返回值
This function returns a string or an array with the replaced values.

用PHP定义一个函数，返回3个参数中的最大值？

我爱编程网(https://www.52biancheng.com)小编还为大家带来用PHP定义一个函数，返回3个参数中的最大值？的相关内容。

可以使用以下代码定义一个函数，返回3个参数中的最大值：
function findMax($num1, $num2, $num3) {
$max = $num1;
if ($num2 > $max) {
$max = $num2;
}
if ($num3 > $max) {
$max = $num3;
}
return $max;
}
该函数接受3个参数 $num1, $num2, $num3，并使用 if 语句判断它们之间的大小关系，返回最大值 $max。可以通过以下方式调用该函数：
echo findMax(5, 9, 3); // 输出 9
在调用函数时，传递3个参数 5, 9 和 3，函数返回 9，这是三个参数中的最大值。

以上就是我爱编程网小编给大家带来的php函数设定参数类型（php str_replace()函数的用法，有那些参数？），希望能对大家有所帮助。更多相关文章关注我爱编程网：www.52biancheng.com

免责声明：文章内容来自网络，如有侵权请及时联系删除。