PHP polymorphic code examples
This article mainly introduces PHP polymorphic code examples. This article uses 2 code examples to demonstrate polymorphism in PHP. Friends who need it can For reference
Polymorphic definition: only care about an interface or base class, not the specific class of an object. (Same type, different results)
Here are two examples:
First, we found that the base class defines the standard and the subclass implements its own rules. This is a requirement of polymorphism. At the same time, this is to satisfy rewriting; in fact, it is a different performance of different classes; it does not strictly satisfy an interface or base class programming. Because when you call it, it is not stu->showGrade() but its own method;
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class stu{ public function showGrade(){ echo "base class"; } } class xiaomin extends stu{ public function showGrade(){ echo "is son show 80"; } } class xiaoli extends stu{ public function showGrade(){ echo "is son show 60"; } } function doit($obj){ if(get_class($obj) != "stu"){ $obj->showGrade(); } } doit(new xiaoli()); doit(new xiaomin()); |
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interface animal{
public function voice();
}
class cat implements animal{
public function voice(){
echo "miao~~~ "; } } class dog implements animal{ public function voice(){ echo "wang ~~~ "; } } function dovoice(animal $obj){ $obj->voice(); } dovoice(new dog()); dovoice(new cat()); |

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

查找方法:1、用strpos(),语法“strpos("字符串值","查找子串")+1”;2、用stripos(),语法“strpos("字符串值","查找子串")+1”。因为字符串是从0开始计数的,因此两个函数获取的位置需要进行加1处理。


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