---
title: "<<(_:_:)"
framework: swift
role: symbol
role_heading: Operator
path: "swift/int64/__(_:_:)-7p8tu"
---

# <<(_:_:)

Returns the result of shifting a value’s binary representation the specified number of digits to the left.

## Declaration

```swift
static func << <RHS>(lhs: Self, rhs: RHS) -> Self where RHS : BinaryInteger
```

## Parameters

- `lhs`: The value to shift.
- `rhs`: The number of bits to shift lhs to the left.

## Discussion

Discussion The << operator performs a smart shift, which defines a result for a shift of any value. Using a negative value for rhs performs a right shift using abs(rhs). Using a value for rhs that is greater than or equal to the bit width of lhs is an overshift, resulting in zero. Using any other value for rhs performs a left shift on lhs by that amount. The following example defines x as an instance of UInt8, an 8-bit, unsigned integer type. If you use 2 as the right-hand-side value in an operation on x, the value is shifted left by two bits. let x: UInt8 = 30                 // 0b00011110 let y = x << 2 // y == 120                       // 0b01111000 If you use 11 as rhs, x is overshifted such that all of its bits are set to zero. let z = x << 11 // z == 0                         // 0b00000000 Using a negative value as rhs is the same as performing a right shift with abs(rhs). let a = x << -3 // a == 3                         // 0b00000011 let b = x >> 3 // b == 3                         // 0b00000011