Recently learning PHPObject-orientedProgramming, I feel that object-oriented thinking does play a huge role in solving complex problems. I can’t imagine if the StarCraft game was developed How complicated it is without using object-oriented thinking. Object-oriented thinking is indeed a major progress in the history of computer programming methods.
Today I want to call another class method as its callback function in the class method I created. I wanted to write the name of another class method directly in the place of the callback function. However, I kept getting an error saying "the parameter is invalid". Then I thought about whether I should try using the SELF keyword, but I still got this error. I really don’t know what to do. I checked the Chinese manual and couldn’t find a solution. Then I carefully looked at the manual on the PHP official website. This manual has the syntax to solve this problem.
class utils{ public function array_or( $input ) { return array_reduce( $input, array('Utils','sum' ), 0 ); } public function sum( $v, $w ) { return $v += $w; } } $uti = new utils; $a = array(1,2,3,4,5); echo $uti->array_or($a);
makes me feel very strange. Why is calling another class method in the form of array? It seems that using the SELF keyword is more appropriate. Hey, I really don’t know what they are doing. What considerations go into designing such a grammar. But I think there must be a reason for the design like this, but I haven't realized this reason yet.
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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。

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。

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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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