PHP Learning with notes 1

<?php # 1. Hello World Header ("Content-type:text/html;charset=utf-8"), #解决中文乱码echo "Hello World"; # 2. Variable string What the # must be the $ symbol at the beginning of the use of this he will take this he = 1; $b = 3; $c = $a + $b; echo "\n$c"; #据说双引号里的变量名称会被替换成实际值echo ' \n$c '; #单引号还不支持转义字符!!    Echo ' <br> first newline ', Echo ' <br> second newline ';#<<< notation defines a string method #首先设置一个结束符号 #这个符号必须单独放在一个行的行首位置 #不然不能识别    #结束符必须单独一行echo <<<std<br> Hello <br> but not good std; #数组 $arr 1 = Array (' You ', ' good ');    echo "<br> $arr 1[1]";    $arr 2 = Array (0=> ' n ');    echo "<br> $arr 2[0]";    #常量 define (' Bitch ', 111); echo "<br>". Bitch. $arr 2[0]; #用. To connect the string and the variable echo "<br>". __file__; #php提供了几个常量 This is one of the #变量的作用域 # 1) function inside the scope is function # 2) Outside the function is the entire PHP but the user-defined letter    Number cannot be used # to use must use $heng = ' ha ';    function Hello () {global $heng;    echo "<br>". $heng;    } hello ();    #动态变量 #并不是我想的那样/* $a 1 = 1;    $b 1 = $a 1;    echo "<br>". $b 1;    $a 1 = 2; echo "<br>". $b 1;*/$chang _name = "trans"; $trans = ' Can see ME ';        echo "<br> $chang _name----$ $chang _name"; #php内置好多预定义的变量 must be assigned to one of our own defined #变量才能用 reference http://php.net/manual/zh/reserved.variables.php $host = $_server[' http    _host '];    echo "<br> $host"; #字符串运算符 #只有. This operation symbol cannot use the plus sign echo "<br> $a". $b ";//13 echo" <br> ".    ("$a" + "$b");//4 #连接字符 $a. = $b; #相当于 $a = $a. $b;    echo "<br>". $a; #逻辑运算 && = and, | |    = OR, Xor is true if ($a and $b) {echo ' <br> condition set ';    } #@ Mask Error message $worry = @ (5/0);    #php函数 similar to JavaScript function HelloWorld () {echo "<br><B>nihao</B>";    } HelloWorld ();    #引用传值 the same as C + +, the default parameter is $a 10 = 8;    Function Zijia (& $a) {$a + = 10;    } Zijia ($a 10);    echo "<br> $a 10";    #支持变量函数 the so-called variable function is to call the function using the variable name $func = "HelloWorld";    $func ();    #对函数的引用的就是对函数返回值的应用 function h () {return "HelloWorld";    } $aaaa = h ();    echo "<br>". $aaaa; #声明一个引用类型的函数 #发现引用函数不能直接返回一个常量 #所It can be foreseen that it returns a variable #地址 instead of copy a value directly to the Received variable function &hh () {$str = "HelloWorld";    return $str;    } $bbbb = &hh ();    echo "<br> $bbbb"; #当引用结束的时候可以通过unset () to dereference #php命名规范 #类名使用驼峰法 #类属性前面就前缀m #类的方法命名 general rule prefixes such as the is Get Set #变量使用小驼峰命名 #引用变量要有前缀r The global variable has the G prefix static variable using the s prefix #变量分割使用_ #方法, the class does not use the _ but the case is able to #php流程控制语句 and other languages as much as a foreach () #类似于java的增强for循环 #在一个 Complex PHP pages may contain multiple conditional statements, and looping statements #和函数 using {} can be cumbersome, so PHP provides another way to use ":" #代替 "{" and "end*" instead of "}" #支持endif, ENDWHILE,ENDFOR,ENDREAC    H,endswitch $s = 1;    echo "<br>";    while ($s + + <): echo "I love you <br>";    Endwhile; ?>

PHP Learning with notes 1