expression1 << expression2

Converts expression1 and expression2 to 32-bit integers, and shifts all the bits in expression1 to the left by the number of places specified by the integer resulting from the conversion of expression2. The bit positions that are emptied as a result of this operation are filled in with 0 and bits shifted off the left end are discarded. Shifting a value left by one position is the equivalent of multiplying it by 2.

Floating-point numbers are converted to integers by discarding any digits after the decimal point. Positive integers are converted to an unsigned hex value with a maximum value of 4294967295 or 0xFFFFFFFF; values larger than the maximum have their most significant digits discarded when they are converted so the value is still 32-bit. Negative numbers are converted to an unsigned hex value via the two's complement notation, with the minimum being -2147483648 or 0x800000000; numbers less than the minimum are converted to two's complement with greater precision and also have the most significant digits discarded.

The return value is interpreted as a two's complement number with sign, so the return value will be an integer in the range -2147483648 to 2147483647.

Operands

expression1 : Number - A number or expression to be shifted left.

expression2 : Number - A number or expression that converts to an integer from 0 to 31.

Returns

Number - The result of the bitwise operation.

Example

In the following example, the integer 1 is shifted 10 bits to the left: x = 1 << 10 The result of this operation is x = 1024. This is because 1 decimal equals 1 binary, 1 binary shifted left by 10 is 10000000000 binary, and 10000000000 binary is 1024 decimal. In the following example, the integer 7 is shifted 8 bits to the left: x = 7 << 8 The result of this operation is x = 1792. This is because 7 decimal equals 111 binary, 111 binary shifted left by 8 bits is 11100000000 binary, and 11100000000 binary is 1792 decimal. If you trace the following example, you see that the bits have been pushed two spaces to the left:

// 2 binary == 0010 
// 8 binary == 1000 
trace(2 << 2); // output: 8 

See also

>>= bitwise right shift and assignment operator, >> bitwise right shift operator, <<= bitwise left shift and assignment operator, >>> bitwise unsigned right shift operator, >>>= bitwise unsigned right shift and assignment operator