js shift operator usage

js shift operator usage is to perform displacement operations on numbers. Shift operators include left shift, right shift and unsigned right shift. They can be used to perform displacement operations on numbers. The binary representation moves left or right by the specified number of bits and returns the result. The shift operator has certain uses in some specific scenarios, such as optimizing calculations and bit mask operations, but in general, the shift operator is rarely used.

#The shift operator in JavaScript is used to perform displacement operations on numbers. Shift operators include left shift (<<), right shift (>>) and unsigned right shift (>>>). These operators shift the binary representation of a number to the left or right by a specified number of places and return the result.

1. Left shift operator (<<):

The left shift operator moves the binary representation of a number to the left by the specified number of digits. After the move, the vacated bits on the right will be filled with 0s. The syntax of the left shift operator is as follows:

   result = number << count;

Among them, number is the number to be shifted, count is the number of digits to be moved, and result is the result after the shift.

Example:

   var number = 5; // 二进制表示为 00000101
   var count = 2; // 向左移动2位
   var result = number << count; // 结果为 20，二进制表示为 00010100

2. Right shift operator (>>):

The right shift operator moves the binary representation of a number to the right by the specified number of digits . After the shift, the vacated bits on the left are filled with the sign bit of the number (0 for positive numbers, 1 for negative numbers). The syntax of the right shift operator is as follows:

   result = number >> count;

Among them, number is the number to be shifted, count is the number of digits to be moved, and result is the result after the shift.

Example:

   var number = 20; // 二进制表示为 00010100
   var count = 2; // 向右移动2位
   var result = number >> count; // 结果为 5，二进制表示为 00000101

3. Unsigned right shift operator (>>>):

The unsigned right shift operator shifts the binary representation of a number to Shift right by specified number of digits. After the shift, the vacated bits on the left will be filled with 0s. The syntax of the unsigned right shift operator is as follows:

   result = number >>> count;

Among them, number is the number to be shifted, count is the number of digits to be moved, and result is the result after the shift.

Example:

   var number = -5; // 二进制表示为 11111111111111111111111111111011
   var count = 2; // 向右移动2位
   var result = number >>> count; // 结果为 1073741822，二进制表示为 00111111111111111111111111111110

The application scenarios of shift operators in JavaScript are relatively limited, but they still have certain uses in some specific situations, such as:

1. Optimize calculations: Shift operations can be used to replace multiplication and division operations because shift operations are more efficient than multiplication and division operations. In some scenarios that require a large number of multiplication or division operations, you can consider using the shift operator for optimization.

2. Bit mask operation: Shift operations can be used to create and operate bit masks. Bit masking is a technique for marking and extracting binary bits, often used to deal with problems related to bit manipulation.

It should be noted that the shift operator can only be used to process 32-bit signed integers (Number type in JavaScript). If the number being operated on exceeds the 32-bit range, the behavior of the shift operator will be undefined. Furthermore, the shift operator does not change the type of the original number, the result is still a 32-bit signed integer.

In summary, the shift operators in JavaScript include left shift (<<), right shift (>>) and unsigned right shift (>>>) . They can be used to perform bit-shift operations on numbers, shifting the binary representation of a number to the left or right by a specified number of bits, and returning the result. Shift operators have certain uses in some specific scenarios, such as optimization calculations and bit mask operations. But in general, we rarely use shift operators.

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