📅 最后修改于: 2020-10-19 03:49:59 🧑 作者: Mango
运算符定义了将在数据上执行的一些函数。运算符作用的数据称为操作数。考虑以下表达式-
7及以上5 = 12
此处，值7、5和12是操作数，而＆plus;和=是运算符。
TypeScript中的主要运算符可以分类为-
假设变量a和b中的值分别为10和5。
| Operator | Description | Example |
|---|---|---|
| + (Addition) | returns the sum of the operands | a + b is 15 |
| – (Subtraction) | returns the difference of the values | a – b is 5 |
| * (Multiplication) | returns the product of the values | a * b is 50 |
| / (Division) | performs division operation and returns the quotient | a / b is 2 |
| % (Modulus) | performs division operation and returns the remainder | a % b is 0 |
| ++ (Increment) | Increments the value of the variable by one | a++ is 11 |
| — (Decrement) | Decrements the value of the variable by one | a– is 9 |
关系运算符测试或定义两个实体之间的关系类型。关系运算符返回布尔值，即true / false。
假设A的值为10，B的值为20。
| Operator | Description | Example |
|---|---|---|
| > | Greater than | (A > B) is False |
| < | Lesser than | (A < B) is True |
| >= | Greater than or equal to | (A >= B) is False |
| <= | Lesser than or equal to | (A <= B) is True |
| == | Equality | (A == B) is false |
| != | Not equal | (A != B) is True |
逻辑运算符用于组合两个或多个条件。逻辑运算符也返回布尔值。假设变量A的值为10，而B为20。
| Operator | Description | Example |
|---|---|---|
| && (And) | The operator returns true only if all the expressions specified return true | (A > 10 && B > 10) is False |
| || (OR) | The operator returns true if at least one of the expressions specified return true | (A > 10 || B >10) is True |
| ! (NOT) | The operator returns the inverse of the expression’s result. For E.g.: !(>5) returns false | !(A >10 ) is True |
假设变量A = 2和B = 3
| Operator | Description | Example |
|---|---|---|
| & (Bitwise AND) | It performs a Boolean AND operation on each bit of its integer arguments. | (A & B) is 2 |
| | (BitWise OR) | It performs a Boolean OR operation on each bit of its integer arguments. | (A | B) is 3 |
| ^ (Bitwise XOR) | It performs a Boolean exclusive OR operation on each bit of its integer arguments. Exclusive OR means that either operand one is true or operand two is true, but not both. | (A ^ B) is 1 |
| ~ (Bitwise Not) | It is a unary operator and operates by reversing all the bits in the operand. | (~B) is -4 |
| << (Left Shift) | It moves all the bits in its first operand to the left by the number of places specified in the second operand. New bits are filled with zeros. Shifting a value left by one position is equivalent to multiplying it by 2, shifting two positions is equivalent to multiplying by 4, and so on. | (A << 1) is 4 |
| >> (Right Shift) | Binary Right Shift Operator. The left operand’s value is moved right by the number of bits specified by the right operand. | (A >> 1) is 1 |
| >>> (Right shift with Zero) | This operator is just like the >> operator, except that the bits shifted in on the left are always zero. | (A >>> 1) is 1 |
| Operator | Description | Example |
|---|---|---|
| = (Simple Assignment) | Assigns values from the right side operand to the left side operand | C = A + B will assign the value of A + B into C |
| += (Add and Assignment) | It adds the right operand to the left operand and assigns the result to the left operand. | C += A is equivalent to C = C + A |
| -= (Subtract and Assignment) | It subtracts the right operand from the left operand and assigns the result to the left operand. | C -= A is equivalent to C = C – A |
| *= (Multiply and Assignment) | It multiplies the right operand with the left operand and assigns the result to the left operand. | C *= A is equivalent to C = C * A |
| /= (Divide and Assignment) | It divides the left operand with the right operand and assigns the result to the left operand. |
注–相同的逻辑适用于按位运算符，因此它们将变为<< =，>> =，>> =，＆=，| =和^ =。
更改值的符号。让我们举个例子。
var x:number = 4
var y = -x;
console.log("value of x: ",x); //outputs 4
console.log("value of y: ",y); //outputs -4
编译时，它将生成以下JavaScript代码。
//Generated by typescript 1.8.10
var x = 4;
var y = -x;
console.log("value of x: ", x); //outputs 4
console.log("value of y: ", y); //outputs -4
它将产生以下输出-
value of x: 4
value of y: -4
＆plus;运算符应用于字符串，会将第二个字符串附加到第一个字符串。以下示例有助于我们理解这一概念。
var msg:string = "hello"+"world"
console.log(msg)
编译时，它将生成以下JavaScript代码。
//Generated by typescript 1.8.10
var msg = "hello" + "world";
console.log(msg);
它将产生以下输出-
helloworld
串联操作不会在字符串之间添加空格。可以在单个语句中连接多个字符串。
该运算符用于表示条件表达式。条件运算符有时也称为三元运算符。语法如下所示-
Test ? expr1 : expr2
测试-指条件表达式
expr1-如果条件为真，则返回值
expr2-如果条件为假，则返回值
让我们看一下下面的代码-
var num:number = -2
var result = num > 0 ?"positive":"non-positive"
console.log(result)
第2行检查变量num中的值是否大于零。如果num被设置为一个值大于零，则返回字符串a€œpositiveâ€其他字符串是一个€œnon-positiveâ€返回。
编译时，它将生成以下JavaScript代码。
//Generated by typescript 1.8.10
var num = -2;
var result = num > 0 ? "positive" : "non-positive";
console.log(result);
上面的代码片段将产生以下输出-
non-positive
它是一元运算运算符。该运算符返回操作数的数据类型。看下面的例子-
var num = 12
console.log(typeof num); //output: number
编译时，它将生成以下JavaScript代码。
//Generated by typescript 1.8.10
var num = 12;
console.log(typeof num); //output: number
它将产生以下输出-
number
该运算符可用于测试对象是否为指定类型。使用instanceof运算符的一章中讨论班。