PHP string processing function example study notes

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        <?php // put your code here 字符串的输出函数echo()
        $str = "Hello World";
        echo $str;
        ?>
    

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        <?php // put your code here程序报错后终止继续运行的函数die()
        $conn = @mysql_connect("localhost", "root", "root") or die("数据库连接失败！");
        ?>
    

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        <?php // put your code here打印函数print_r()
        $arr = array(&#39;0&#39;=>'PHP',"1"=>array('0'=>'P', '1'=>'H', '2'=>'P'));
        print_r($arr);
        ?>
    

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        <?php // put your code here字符串分割函数explode()
        $str = "PHP,JSP,JAVA,C++,HTML";
        print_r(explode(",",$str));
        ?>
    

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        <?php // put your code here数组元素组合成字符串的函数implode()
        $arr = array(&#39;Hello&#39;, &#39;World!&#39;, &#39;Beautiful&#39;, &#39;Day!&#39;);
        echo implode(" ", $arr);
        ?>
    

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        <?php // put your code here预定义字符串转换为HTML实体的函数htmlspecialchars()
        $str = "<strong>PHP100.COM";
        echo htmlspecialchars($str);
        ?>
    

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        <?php // put your code here
        $str = "<font color=&#39;red&#39;>PHP + <em>Apache</em> + <b>Mysql</b>";
        echo strip_tags($str);
        echo "<br>";
        echo strip_tags($str, "<font>");
        echo "<br>";
        echo strip_tags($str, "<font><em><b>");
        ?>
    

</b></em></font></font>

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        <?php // put your code here去除字符串首尾连续空格的函数
        $str = "  PHP100  ";
        echo strlen($str)."<br>";
        echo strlen(ltrim($str))."<br>";
        echo strlen(rtrim($str))."<br>";
        echo strlen(trim($str));
        ?>
    

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        <?php // put your code here
        echo nl2br("PHP100.COM \n PHP100.NET");
        ?>
    

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        <?php // put your code here加密函数MD5
        $str = "PHP100.COM";
        echo md5($str);
        ?>
    

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        <?php // put your code here加密函数sha1()
        $str = "PHP100.COM";
        echo sha1($str);
        ?>
    

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        <?php // put your code here字符串替换函数str_replace()
        $str = "baidu.com";
        echo str_replace("baidu", "php100", $str);
        ?>
    

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        <?php // put your code here数字分组格式化函数number_format()
        $number = "1234567890";
        echo number_format($number);
        echo "<br/>";
        echo number_format($number,2);
        echo "<br>";
        echo number_format($number,2,",",".");
        ?>
    

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        <?php // put your code here字符串分割函数str_split()
        $str = "Hello World";
        $arr1 = str_split($str);
        $arr2 = str_split($str,3);
        print_r($arr1);
        print_r($arr2);
        
        ?>
    

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        <?php // put your code here字符串截取函数substr()
        echo substr("WWW.PHP100.COM", 4);
        ?>
    

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        <?php // put your code here
        $str = "我是一名PHP程序员";
        echo iconv(&#39;UTF-8&#39;, &#39;GBK&#39;, $str);
        echo iconv_substr($str, "2", "2", "UTF-8");
        ?>
    

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