PHP中的运算符类型:
1.算术运算符
2.递增/递减运算符
3.比较运算符
4.逻辑运算符
5.位运算符
6.其他运算符
示例:
";
echo $b." ".base_convert($b, 10, 2);
echo "
----------------------
";
echo "按位与: ",$a & $b," ", decbin($a&$b), "
";
echo "按位或: ",$a | $b," ", decbin($a|$b), "
";
echo "按位异或: ",$a ^ $b," ", decbin($a^$b), "
";
echo "按位非: ",~$a," ", decbin(~$a), "
";
echo "左移一位: ",$a << 1," ", decbin($a<<1), "
";
echo "右移一位: ",$a >> 1," ", decbin($a>>1), "
";
?>
5 101
6 110
----------------------
按位与: 4 100
按位或: 7 111
按位异或: 3 11
按位非: -6 11111111111111111111111111111010
左移一位: 10 1010
右移一位: 2 10
例:
$str1 = "google chrome";
$rm = "bbs.rainmeter.cn";
$str2 = "".$str1.$rm."
"."-----------
"; //全部拼在一起就是结果
echo $str2;
echo $str1.=" addedplus"; //结果:google chrome addedplus
echo '--------------------------------';
$a = 1;
$a .= 2;
echo $a; //此处发生类型转换,结果当然是字符串12
echo '--------------------------------';
$file_name = "helo.txt"; //此处故意将hello.txt打错
$file = @fopen($file_name, 'r'); //可以将warning信息屏蔽,但错误依然存在,开发阶段不建议这样做
$content = fread($file, filesize($file_name));
echo $content; //warning报错
echo '--------------------------------';
$t = 0;
$msg = $t>0 ? 't大于0' : 't不大于0';
$uname = isset($_GET['uname'])?$_GET['uname']:'未被定义';
echo $uname; //$uname之前未被定义,因此结果为字符串
&& || 存在短路特性
& | 不存在短路
$file = @fopen('hello.txt', 'r') or die('文件不存在,a.txt必须存在'); //@屏蔽错误消息
简单例子:
'123456', 'tt'=>'555', 'sina'=>'888','bbs'=>'999');
$uname = isset($_POST['uname'])?$_POST['uname']:'';
$upwd = isset($_POST['upwd'])?$_POST['upwd']:'';
if(in_array($uname,$user_arr)){
if($upwd == $upwd_arr[$uname]){
echo '登录成功,现在转入后台操作页面……';
$ok = true;
}else{
echo('密码错误');
}
}else{
echo('用户名不存在');
}
?>
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以上均为个人理解,初学php,如果有不对的地方,欢迎大家指正!