1.第一个PHP程序
<span 1</span> <span //</span><span 弱爆了有木有</span> <span 2</span> <?<span php </span><span 3</span> <span echo</span> "<span Hello PHP!'; </span><span 4</span> ?>
2.PHP共支持8种基本数据理性，包括4种标量类型：boolean（布尔型）、integer（整型）、float（浮点型，也称为double）、string（字符串），2种复合类型：array（数组）、object（对象），2种特殊类型：resource（资源）、NULL（空类型）
3.函数var_dump可以用来打印变量的相关信息。
<span 1</span> <?<span php </span><span 2</span> <span var_dump</span>((bool) <span false</span><span ); </span><span 3</span> <span var_dump</span>((bool) 0<span ); </span><span 4</span> <span var_dump</span>((bool) 0.0<span ); </span><span 5</span> <span var_dump</span>((bool) ''<span ); </span><span 6</span> <span var_dump</span>((bool) "0"<span ); </span><span 7</span> <span var_dump</span>((bool) <span array</span><span ()); </span><span 8</span> <span var_dump</span>((bool) <span NULL</span><span ); </span><span 9</span> ?>
4.关于整型。
在32位操作系统中，整型数的有效范围是-2147483648~+2147483647。如果超过了这个范围，将会被PHP引擎解释成浮点数（float）。
用八进制加0，用十六进制加0x（是数字0而非字母O）
<span 1</span> <?<span php </span><span 2</span> <span $dec_int</span>=63<span ; </span><span 3</span> <span var_dump</span>(<span $dec_int</span><span ); </span><span 4</span> <span 5</span> <span $oct_int</span>=077<span ; </span><span 6</span> <span var_dump</span>(<span $oct_int</span><span ); </span><span 7</span> <span 8</span> <span $hex_int</span>=0x3f<span ; </span><span 9</span> <span var_dump</span>(<span $hex_int</span><span ); </span><span 10</span> ?>
5.字符串型
有3种定义字符串的方式，分别是单引号（‘）、双引号（“）和界定符（<<<）。前面2个的区别是，假如字符串中包含变量名，双引号中的变量名会被实际值替代，而单引号中的变量名会按普通字符直接输出。
<span 1</span> <?<span php </span><span 2</span> <span $name</span>='麦兜'<span ; </span><span 3</span> <span $age</span>=19<span ; </span><span 4</span> <span echo</span> '本人大名$name，年方$age'<span ; </span><span 5</span> <span echo</span> '<p>'<span ; </span><span 6</span> <span echo</span> "本人大名<span $name</span>,年方<span $age</span>"<span ; </span><span 7</span> ?>
关于界定符使用如下：
<span 1</span> <?<span php </span><span 2</span> <span echo</span> <<<<span MY_STR </span><span 3</span> <span 我是PHP初学者 </span><span 4</span> <span MY_STR; //最后结尾的标识符前面不能有空格或者缩进，必须顶咯 </span><span 5</span> ?>
6.对象类型
<span 1</span> <?<span php
</span><span 2</span> <span class</span><span Person {
</span><span 3</span> <span public</span> <span $name</span><span ;
</span><span 4</span> <span private</span> <span $age</span><span ;
</span><span 5</span>
<span 6</span> <span function</span> Person(<span $name</span>,<span $age</span><span ){
</span><span 7</span> <span $this</span>->name=<span $name</span><span ;
</span><span 8</span> <span $this</span>->age=<span $age</span><span ;
</span><span 9</span> <span }
</span><span 10</span>
<span 11</span> <span function</span><span getInfo(){
</span><span 12</span> <span echo</span> '我叫'.<span $this</span>->name.'<br>我今年'.<span $this</span>->age.'岁了'<span ;
</span><span 13</span> <span }
</span><span 14</span> <span }
</span><span 15</span> <span $boy</span> = <span new</span> Person("kimi",5<span );
</span><span 16</span> <span $boy</span>-><span getInfo();
</span><span 17</span> ?> 7.类型转换
print_r() 显示关于一个变量的易于理解的信息。如果给出的是 string、integer 或 float，将打印变量值本身。如果给出的是 array，将会按照一定格式显示键和元素
<span 1</span> <?<span php </span><span 2</span> <span $temp_var</span>=3.141592653<span ; </span><span 3</span> <span $var1</span>=(<span string</span>)<span $temp_var</span><span ; </span><span 4</span> <span echo</span> "<p><span $var1</span>"<span ; </span><span 5</span> <span 6</span> <span $temp_var</span>='Kimi'<span ; </span><span 7</span> <span $var2</span>=(<span array</span>)<span $temp_var</span><span ; </span><span 8</span> <span echo</span> '<p>'<span ; </span><span 9</span> <span print_r</span>(<span $var2</span><span ); </span><span 10</span> <span 11</span> <span $temp_var</span>='Cindy'<span ; </span><span 12</span> <span $var3</span>=(<span unset</span>)<span $temp_var</span><span ; </span><span 13</span> <span echo</span> '<p>'<span ; </span><span 14</span> <span var_dump</span>(<span $var3</span><span ); </span><span 15</span> ?>
