📅 最后修改于: 2020-10-16 05:14:22 🧑 作者: Mango
运算符是一个符号，告诉解释器执行特定的数学或逻辑操作。 Lua语言具有丰富的内置运算符，并提供以下类型的运算符-
本教程将逐一说明算术，关系，逻辑和其他各种运算符。
下表显示了Lua语言支持的所有算术运算运算符。假设变量A持有10，变量B持有20，则-
| Operator | Description | Example |
|---|---|---|
| + | Adds two operands | A + B will give 30 |
| – | Subtracts second operand from the first | A – B will give -10 |
| * | Multiply both operands | A * B will give 200 |
| / | Divide numerator by de-numerator | B / A will give 2 |
| % | Modulus Operator and remainder of after an integer division | B % A will give 0 |
| ^ | Exponent Operator takes the exponents | A^2 will give 100 |
| – | Unary – operator acts as negation | -A will give -10 |
下表显示了Lua语言支持的所有关系运算符。假设变量A持有10，变量B持有20，则-
| Operator | Description | Example |
|---|---|---|
| == | Checks if the value of two operands are equal or not, if yes then condition becomes true. | (A == B) is not true. |
| ~= | Checks if the value of two operands are equal or not, if values are not equal then condition becomes true. | (A ~= B) is true. |
| > | Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true. | (A > B) is not true. |
| < | Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true. | (A < B) is true. |
| >= | Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true. | (A >= B) is not true. |
| <= | Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true. | (A <= B) is true. |
下表显示了Lua语言支持的所有逻辑运算符。假设变量A为真，变量B为假，则-
| Operator | Description | Example |
|---|---|---|
| and | Called Logical AND operator. If both the operands are non zero then condition becomes true. | (A and B) is false. |
| or | Called Logical OR Operator. If any of the two operands is non zero then condition becomes true. | (A or B) is true. |
| not | Called Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true then Logical NOT operator will make false. | !(A and B) is true. |
Lua语言支持的其他运算符包括串联和长度。
| Operator | Description | Example |
|---|---|---|
| .. | Concatenates two strings. | a..b where a is “Hello ” and b is “World”, will return “Hello World”. |
| # | An unary operator that return the length of the a string or a table. | #”Hello” will return 5 |
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-
例如，x = 7 + 3 * 2;在这里给x分配13，而不是20，因为运算符*的优先级比＆plus;的优先级高。因此它首先乘以3 * 2，然后加到7。
在此，优先级最高的运算符出现在表格的顶部，而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评估。
| Category | Operator | Associativity |
|---|---|---|
| Unary | not # – | Right to left |
| Concatenation | .. | Right to left |
| Multiplicative | * / % | Left to right |
| Additive | + – | Left to right |
| Relational | < > <= >= == ~= | Left to right |
| Equality | == ~= | Left to right |
| Logical AND | and | Left to right |
| Logical OR | or | Left to right |