第六课 运算符
一、赋值运算符 =
示例代码1:
result = num1 + num2;
days = ["Mon","Tue","Wed","Thu","Fri"];
二、算术运算符 +-*/
+ (additive operator) - (subtraction operator) * (multiplication operator) / (division operator) mod (remainder operator) 示例代码2: var result = 1 + 2; // result is now 3 println(result); result = result - 1; // result is now 2 println(result); result = result * 2; // result is now 4 println(result); result = result / 2; // result is now 2 println(result); result = result + 8; // result is now 10 println(result); result = result mod 7; // result is now 3 println(result); 也可以缩写运算符 += -= *= /= 示例代码3: var result = 0; result += 1; println(result); // result is now 1 result -= 1; println(result); // result is now 0 result = 2; result *= 5; // result is now 10 println(result); result /= 2; // result is now 5 println(result); |
一元运算符
- Unary minus operator; negates a number ++ Increment operator; increments a value by 1 -- Decrement operator; decrements a value by 1 not Logical complement operator; inverts the value of a boolean
示例代码4:
var result = 1; // result is now 1 result--; // result is now 0 println(result); result++; // result is now 1 println(result); result = -result; // result is now -1 println(result); var success = false; println(success); // false println(not success); // true
自增自减运算符
示例代码5:
var result = 3;
result++;
println(result); // result is now 4
++result;
println(result); // result is now 5
println(++result); // result is now 6
println(result++); // this still prints 6!
println(result); // but the result is now 7
关系运算符
== 等于 != 不等于 > 大于 >= 大于等于 < 小于 <= 小于等于
示例代码6:
def num1 = 1; def num2 = 2; println(num1 == num2); // prints false println(num1 != num2); // prints true println(num1 > num2); // prints false println(num1 >= num2); // prints false println(num1 < num2); // prints true println(num1 <= num2); // prints true
条件运算符
and
or
示例代码7:
def username = "foo"; def password = "bar"; if ((username == "foo") and (password == "bar")) { println("Test 1: username AND password are correct"); } if ((username == "") and (password == "bar")) { println("Test 2: username AND password is correct"); } if ((username == "foo") or (password == "bar")) { println("Test 3: username OR password is correct"); } if ((username == "") or (password == "bar")) { println("Test 4: username OR password is correct"); }
输出:
Test 1: username AND password are correct Test 3: username OR password is correct Test 4: username OR password is correct
类型比较运算符
instanceof
def str1="Hello"; println(str1 instanceof String); // prints true def num = 1031; println(num instanceof java.lang.Integer); // prints true