1234567891011121314151617181920212223242526272829303132333435363738 |
- <?php
- echo 'hello world';
- $var1 =5;
- $var2 = 1;
- echo $var2;
- $var2 = 2;
- echo $var2;
- unset($var2);
- $a = 'b';
- $b = 'bb';
- echo $a;
- echo $$a;
- //使用函数定义常量:define
- define('PI',3.14);
- const PII = 3;
- define('-_-',smile);
- const -_- = smile;
- echo -_-;
- echo constant('-_-');
- //系统常量
- echo phpversion,php_int_size,php_int_max;
- //数据类型
- $a = 'abc1.1.1';
- $b = '1.1.1abc';
- echo $a + $b;//自动转化
- echo '<br/>',(float)$a,(float)$b; //强制转换 //以字母开头的字符串,永远为0;以数字开头的字符串,碰到字符串小数点为止;
- var_dump(is_int($a)); //false
- var_dump(is_string($a));//true
- echo gettype($a);//获取类型,得到的是该类型的对应的字符串 //
|