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Operators
JavaScript has a full range of operators, including arithmetic, logic, bit assignment operator and, in addition there are other operators.
arithmetic:
| description | symbol |
|---|---|
| Negative | - |
| Increment | ++ |
| Decreasing | – |
| multiplication | * |
| division | / |
| Modulo operation | % |
| addition | + |
| Subtraction | - |
logic:
| description | symbol |
|---|---|
| Logical NOT | ! |
| Less than | < |
| more than the | > |
| Less than or equal | <= |
| greater or equal to | >= |
| equal | == |
| not equal to | != |
| Logic and | && |
| Logical or | || |
| Condition (ternary operator) | ?: |
| comma | , |
| Identity | === |
| Nonidentical | !== |
Bit operation: bit arithmetic want to learn more , please click here to explain in detail
| description | symbol |
|---|---|
| Bitwise | ~ |
| Bitwise left shift | << |
| Bitwise Right Shift | >> |
| Unsigned right shift | >>> |
| Bitwise AND | & |
| Bitwise or | | |
| Bitwise XOR | ^ |
Assignment:
| description | symbol |
|---|---|
| Assignment | = |
| Addition assignment | += |
| Subtraction assignment | -= |
| Multiplication assignment | *= |
| Division assignment | /= |
| Modulo assignment | %= |
Operator Precedence
JavaScript is in accordance with a specific operator in order of priority of the evaluation, in this order is the operator.
Here, I Low lists these operators, the operators in the same row from left to right evaluation order.
| Operators | description |
|---|---|
| . [ ] () | Field access, array subscript and function calls |
| ++ – - ~ ！ typeof new void delete | Unary operators, return data type, object creation, undefined values |
| * / % | Multiplication, division, modulo |
| + - + | Addition, subtraction, string concatenation |
| << >> >>> | Displacement |
| < <= > >= | Less than, less than or equal, greater than, greater than or equal |
| == != === !== | Equal, not equal, identity, nonidentical |
| & | Bitwise AND |
| ^ | Bitwise XOR |
| | | Bitwise or |
| && | Logic and |
| || | Logical or |
| ?: | Condition (ternary operator) |
| = | Assignment |
| , | Multiple evaluation |
Having a higher priority operator to be evaluated before a lower priority operators, for example:
z = 78 * (96+3+45)
// 它们将这个顺序求值：(),*,+,+,=
Parentheses may be used to alter the order of evaluation, all of the expression in parentheses should be evaluated before the rest of the for statement.
Operation:
First evaluation of the expression in parentheses: wherein there are two operators addition, they have the same priority: 96 + 3 are added, and then added to the 45, 144 to give a result.
Multiplication is then: 78 and 144 multiplied by the result 11232.
Finally, the assignment operator: 11232 assigned to z.