吴裕雄--天生自然 PHP开发学习：运算符

ゞ浴缸里的玫瑰 2021-11-05 10:36 256阅读 0赞

<?php
 $x=10;
 $y=6;
 echo ($x + $y); // 输出16
 echo ' '; // 换行
 
 echo ($x - $y); // 输出4
 echo ' '; // 换行
 
 echo ($x * $y); // 输出60
 echo ' '; // 换行
 
 echo ($x / $y); // 输出1.6666666666667
 echo ' '; // 换行
 
 echo ($x % $y); // 输出4
 echo ' '; // 换行
 
 echo -$x;
 ?>

![1020928-20190528214128676-1666049836.png][]

<?php
 var_dump(intdiv(10, 3));
 ?>

![1020928-20190528214237548-535969165.png][]

<?php 
 $x=10; 
 echo $x; // 输出10
 
 $y=20; 
 $y += 100;
 echo $y; // 输出120
 
 $z=50;
 $z -= 25;
 echo $z; // 输出25
 
 $i=5;
 $i *= 6;
 echo $i; // 输出30
 
 $j=10;
 $j /= 5;
 echo $j; // 输出2
 
 $k=15;
 $k %= 4;
 echo $k; // 输出3
 ?>

![1020928-20190528214357835-174154018.png][]

<?php
 $a = "Hello";
 $b = $a . " world!";
 echo $b; // 输出Hello world!
 
 $x="Hello";
 $x .= " world!";
 echo $x; // 输出Hello world!
 ?>

<?php
 $x=10;
 echo ++$x; // 输出11
 
 $y=10;
 echo $y++; // 输出10
 
 $z=5;
 echo --$z; // 输出4
 
 $i=5;
 echo $i--; // 输出5
 ?>

![1020928-20190528214749246-1925297667.png][]

<?php
 $x=100;
 $y="100";
 
 var_dump($x == $y);
 echo " ";
 var_dump($x === $y);
 echo " ";
 var_dump($x != $y);
 echo " ";
 var_dump($x !== $y);
 echo " ";
 
 $a=50;
 $b=90;
 
 var_dump($a > $b);
 echo " ";
 var_dump($a < $b);
 ?>

![1020928-20190528214900280-893062545.png][]

<?php
 $x = array("a" => "red", "b" => "green"); 
 $y = array("c" => "blue", "d" => "yellow"); 
 $z = $x + $y; // $x 和 $y 数组合并
 var_dump($z);
 var_dump($x == $y);
 var_dump($x === $y);
 var_dump($x != $y);
 var_dump($x <> $y);
 var_dump($x !== $y);
 ?>

![1020928-20190528215029987-120799927.png][]

<?php
 // 如果 $_GET['user'] 不存在返回 'nobody'，否则返回 $_GET['user'] 的值
 $username = $_GET['user'] ?? 'nobody';
 // 类似的三元运算符
 $username = isset($_GET['user']) ? $_GET['user'] : 'nobody';
 ?>

<?php
 // 整型
 echo 1 <=> 1; // 0
 echo 1 <=> 2; // -1
 echo 2 <=> 1; // 1
 
 // 浮点型
 echo 1.5 <=> 1.5; // 0
 echo 1.5 <=> 2.5; // -1
 echo 2.5 <=> 1.5; // 1
 
 // 字符串
 echo "a" <=> "a"; // 0
 echo "a" <=> "b"; // -1
 echo "b" <=> "a"; // 1
 ?>

![1020928-20190528215342638-411680362.png][]

<?php
 // 优先级： && > = > and
 // 优先级： || > = > or
 
 $a = 3;
 $b = false;
 $c = $a or $b;
 var_dump($c); // 这里的 $c 为 int 值3，而不是 boolean 值 true
 $d = $a || $b;
 var_dump($d); //这里的 $d 就是 boolean 值 true 
 ?>

![1020928-20190528215551017-1648384154.png][]

<?php
 // 括号优先运算
 
 $a = 1;
 $b = 2;
 $c = 3;
 $d = $a + $b * $c;
 echo $d;
 echo "\n";
 $e = ($a + $b) * $c; // 使用括号
 echo $e;
 echo "\n";
 ?>

![1020928-20190528215654209-24105407.png][]

转载于:https://www.cnblogs.com/tszr/p/10940556.html

[1020928-20190528214128676-1666049836.png]: /images/20211104/e00ed5d4517d4cbf9828b3af2fd80a8c.png
[1020928-20190528214237548-535969165.png]: /images/20211104/b3aae4b258d44e0aad2c721d4ba6a3fe.png
[1020928-20190528214357835-174154018.png]: /images/20211104/dd17c89cd2d1474abbc2313099c779f6.png
[1020928-20190528214749246-1925297667.png]: /images/20211104/1ef90fb56cf44e89af103a3c02e4eb12.png
[1020928-20190528214900280-893062545.png]: /images/20211104/0eafa908e4c64c5b8d1fc84644938a53.png
[1020928-20190528215029987-120799927.png]: /images/20211104/3bc70f8f193947338a60a0575f4567b0.png
[1020928-20190528215342638-411680362.png]: /images/20211104/14b3205538a741bda81b59e2991a36e5.png
[1020928-20190528215551017-1648384154.png]: /images/20211104/61e1d67b436246a5b251ca7e39c776a1.png
[1020928-20190528215654209-24105407.png]: /images/20211104/9ab8cf991b0648d2a12badcb449c56cc.png