Scala 运算符

运算符

运算符是一个符号，告诉编译器执行特定的数学或逻辑操作。Scala具有丰富的内置运算符，并提供以下类型的运算符-

• 算术运算符
• 关系运算符
• 逻辑运算符
• 按位运算符
• 赋值运算符

本章将逐一研究算术，关系，逻辑，按位，赋值和其他运算符。

算术运算符

Scala语言支持以下算术运算符。例如，假设变量A持有10，变量B持有20，则-

*示例：**

object Demo {
   def main(args: Array[String]):Unit= {
      var a = 10;
      var b = 20;
      var c = 25;
      var d = 25;

      println("a + b = " + (a + b) );
      println("a - b = " + (a - b) );
      println("a * b = " + (a * b) );
      println("b / a = " + (b / a) );
      println("b % a = " + (b % a) );
      println("c % a = " + (c % a) );
   }
}

输出：

a + b = 30
a - b = -10
a * b = 200
b / a = 2
b % a = 0
c % a = 5

关系运算符

Scala语言支持以下关系运算符。例如，假设变量A持有10，变量B持有20，则-

示例：

object Demo {
   def main(args: Array[String]):Unit= {
      var a = 10;
      var b = 20;

      println("a == b = " + (a == b) );
      println("a != b = " + (a != b) );
      println("a > b = " + (a > b) );
      println("a < b = " + (a < b) );
      println("b >= a = " + (b >= a) );
      println("b <= a = " + (b <= a) );
   }
}

输出：

a == b = false
a != b = true
a > b = false
a < b = true
b >= a = true
b <= a = false

逻辑运算符

Scala语言支持以下逻辑运算符。例如，假设变量A持有1，变量B持有0，则-

示例：

object Demo {
   def main(args: Array[String]):Unit = {
      var a = true;
      var b = false;

      println("a && b = " + (a&&b) );

      println("a || b = " + (a||b) );

      println("!(a && b) = " + !(a && b) );
   }
} 

输出：

a && b = false
a || b = true
!(a && b) = true

按位运算符

按位运算符对位进行运算并逐位执行操作。＆，|和^的真值表如下-

假设A = 60; 和B = 13; 现在以二进制格式，它们将如下所示-

A = 0011 1100
B = 0000 1101
-----------------------
A&B = 0000 1100
A|B = 0011 1101
A^B = 0011 0001
~A = 1100 0011

示例：下表列出了Scala语言支持的按位运算符。假设变量A为60，变量B为13，则-

object Demo {
   def main(args: Array[String]):Unit = {
      var a = 60;           /* 60 = 0011 1100 */  
      var b = 13;           /* 13 = 0000 1101 */
      var c = 0;

      c = a & b;            /* 12 = 0000 1100 */ 
      println("a & b = " + c );

      c = a | b;            /* 61 = 0011 1101 */
      println("a | b = " + c );

      c = a ^ b;            /* 49 = 0011 0001 */
      println("a ^ b = " + c );

      c = ~a;               /* -61 = 1100 0011 */
      println("~a = " + c );

      c = a << 2;           /* 240 = 1111 0000 */
      println("a << 2 = " + c );

      c = a >> 2;           /* 215 = 1111 */
      println("a >> 2  = " + c );

      c = a >>> 2;          /* 215 = 0000 1111 */
      println("a >>> 2 = " + c );
   }
} 

输出：

a & b = 12
a | b = 61
a ^ b = 49
~a = -61
a << 2 = 240
a >> 2 = 15
a >>> 2 = 15

赋值运算符

Scala语言支持以下赋值运算符-

示例：

object Demo {
   def main(args: Array[String]):Unit = {
      var a = 10; 
      var b = 20;
      var c = 0;

      c = a + b;
      println("c = a + b  = " + c );

      c += a ;
      println("c += a  = " + c );

      c -= a ;
      println("c -= a = " + c );

      c *= a ;
      println("c *= a = " + c );

      a = 10;
      c = 15;
      c /= a ;
      println("c /= a  = " + c );

      a = 10;
      c = 15;
      c %= a ;
      println("c %= a  = " + c );

      c <<= 2 ;
      println("c <<= 2  = " + c );

      c >>= 2 ;
      println("c >>= 2  = " + c );

      c >>= 2 ;
      println("c >>= 2  = " + c );

      c &= a ;
      println("c &= a  = " + c );

      c ^= a ;
      println("c ^= a  = " + c );

      c |= a ;
      println("c |= a  = " + c );
   }
} 

输出：

c = a + b  = 30
c += a  = 40
c -= a  = 30
c *= a  = 300
c /= a  = 1
c %= a  = 5
c <<= 2  = 20
c >>= 2  = 5
c >>= 2  = 1
c &= a  = 0
c ^= a  = 10
c |= a  = 10

Scala中的运算符优先级

运算符优先级确定表达式中术语的分组。这会影响表达式的求值方式。某些运算符具有更高的优先级；例如，乘法运算符的优先级比加法运算符高-例如，x = 7 + 3 * 2; 在这里，x被赋值为13，而不是20，因为运算符*的优先级比+高，因此它首先与3 * 2相乘，然后加到7。看看下表。优先级最高的运算符出现在表格的顶部，优先级最低的运算符出现在表格的底部。在表达式中，优先级较高的运算符将首先被计算。