Question

示例字符串：

    public interface Observer {
        /**
          * IF THIS METHOD IS NOT HERE SUBJECT WILL NOT BE ABLE TO CALL IT
          * REFER TO OO BASICS - INHERITANCE
          */
        void update(Subject subject);
    }

    public abstract class Subject {
        // THE COMPLETE LOGIC HERE IS INDEPENDENT OF 
        // WHO THE CONCRETE SUBJECT IS.
        // HENCE THIS IS A RIGHT PLACE FOR IT AS PER OO PRINCIPLES
        // NOTE THAT THIS CLASS KNOWS ONLY ABOUT ABSTRACT OBSERVER
        private Set<Observer> observers; 
        public void add(Observer o){/*...*/}
        public void remove(Observer o){/*...*/}
        protected void notifyAllObservers(){
            for (Observer observer : observers) {
                observer.update(this);
            }
        }
    }

    class ConcreteSubject extends Subject {
        /**
         * HERE THERE IS NO NEED TO KNOW THE CONCRETE OBSERVER-
         * By DEFINITION OF THIS PATTERN. 
         * THE JOB HERE IS TO ONLY NOTIFY ALL OBSERVERS THAT "I HAVE CHANGED"
         * ITS OBSERVER'S RESPONSIBILITY TO REACT IN PULL METHOD
         */

         // Concrete Subject state
         // Concrete Subject behavior
        public void specificMethod(){
            //... concrete class specific logic
        }
    }

    class ConcreteObserver implements Observer{
        @Override
        public void update(Subject subject) {
            /**
             * OBSERVE HERE WE NEED TO TYPE CAST, WHICH LEADS TO VIOLATION OF 
             * OO PRINCIPLES. BUT WE GET BENEFIT OF LOOSELY COUPLED OBSERVERS
             * AGAINST THIS EXTRA COST
             * ITS SAFE TO VIOLATE HERE AS OBSERVER INSTANCES MAKE ONLY 
             * SENSE IN CONTEXT WITH SUBJECT AND WILL NEVER BE REUSED AS
             * OBSERVERS IN UNRELATED CONTEXT.
             */
            ((ConcreteSubject)subject).specificMethod();
        }
    }

必须找到它们：

Here are sample apartment pictures {img="/path/photo1.jpg" alt="I am Photo Title"} and {img="/path/photo2.jpg" alt="I am Photo Title #2"} this...

如何在句子中找到这些图像链接？

Answer 1

<?php

$string = "Here are sample apartment pictures {img='/path/photo1.jpg' alt='I am Photo Title'} and {img='/path/photo2.jpg' alt='I am Photo Title #2'} this...";

preg_match_all("/({([\w]+)[^}]*})(.*?)/", $string, $matches, PREG_SET_ORDER);

foreach ($matches as $val) {
    echo "Variable Word In String: " . $val[1] . "<br>\n";
}


?>

Answer 2

也可以通过爆炸来完成我在这里爆炸＆＃34; {＆＃34;首先删除不以＆＃34开头的数组中的项目; img =＆＃34;。
然后我爆炸＆＃34;}＆＃34;删除右边的多余部分。

作为正则表达式的替代方案，并不是说它比正则表达式或strpos方法更好。

$str ='Here are sample apartment pictures {img="/path/photo1.jpg" alt="I am Photo Title"} and {img="/path/photo2.jpg" alt="I am Photo Title #2"} this...';

$arr = explode("{", $str);
Foreach($arr as $key => &$val){
    if(substr($val,0,4) == "img="){
        $val = "{". explode("}", $val)[0] . "}";
    }else{
        Unset($arr[$key]);
    }
}
Var_dump($arr);

https://3v4l.org/7Zov0

如何在PHP中使用Regex查找字符串中的任何变量字

2 个答案: