Python’s *in-place bitwise right-shift operator*`x >>= y`

calculates the right-shift operation `x >> y`

, and assigns the result to the first operands variable name `x`

. You can set up the in-place right-shift behavior in your own class by overriding the magic “dunder” method `__irshift__(self, other)`

in your class definition.

>>> x = 8 >>> x >>= 2 >>> x 2

The expression `x >>= y`

is syntactical sugar for the longer-form `x = x >> y`

:

>>> x = 8 >>> x = x >> 2 >>> x 2

Let’s explore some examples on different data types of the operands.

## Recap Bitwise Right-Shift

The Python ** bitwise right-shift** operator

`x >> n`

shifts the binary representation of integer `x`

by `n`

positions to the right. It inserts a `0`

bit on the left and removes the right-most bit. For example, if you right-shift the binary representation `0101`

by one position, you’d obtain `0010`

. Semantically, the bitwise right-shift operator is the same as performing integer division by `2**n`

. Here’s a minimal example:

print(8 >> 1) # 4 print(8 >> 2) # 2 print(-3 >> 1) # -2

Here’s a short explainer video too:

**Related. **To learn more about the bitwise right-shift operator, and how it works on positive and negative integers, check out our related tutorial: > Operator”>Python Bitwise Right-Shift Operator

## Incompatible Data Type

What if two operands have an incompatible data type—unlike floats and integers? For example, if you try to shift a float variable by a list variable (which doesn’t make sense)?

>>> x = 3.0 >>> y = [1, 2] >>> x >> y Traceback (most recent call last): File "<pyshell#5>", line 1, in <module> x >> y TypeError: unsupported operand type(s) for >>: 'float' and 'list'

The result of incompatible addition is a `TypeError`

. You can fix it by using only compatible data types for the in-place bitwise right-shift operation.

Can you use the bitwise right-shift operator on custom objects? Yes!

## Python In-Place Bitwise Right-Shift Magic Method

To use the in-place bitwise right-shift operator `>>=`

on custom objects, you need to define the `__irshift__()`

method (*“dunder method”, “magic method”*) that takes two arguments `self`

and `other`

, updates the first argument `self`

with the result of the operation, and returns the updated object.

In the following code, you combine two `Data`

objects using the in-place right-shift operation:

class Data: def __init__(self, data): self.data = data def __irshift__(self, other): self.data >>= other.data return self x = Data(8) y = Data(2) x >>= y print(x.data) # 2

You can see that the content of the first operand is updated as a result of the in-place bitwise right-shift operation.

## Python In-Place Operators

In-place assignment operators (also called *compound* assignment operators) perform an operation in-place on a variable provided as first operand. They overwrite the value of the first operand variable with the result of the operation when performing the operator without assignment. For example, `x += 3`

is the same as `x = x + 3`

of first calculating the result of `x +3`

and then assigning it to the variable x.

Operator | Name | Short Example | Equivalent Long Example |
---|---|---|---|

`=` | In-place Assignment | `x = 3` | |

`+=` | In-place Addition | `x += 3` | `x = x + 3` |

`-=` | In-place Subtraction | `x -= 3` | `x = x - 3` |

`*=` | In-place Multiplication | `x *= 3` | `x = x * 3` |

`/=` | In-place Division | `x /= 3` | `x = x / 3` |

`%=` | In-place Modulo | `x %= 3` | `x = x % 3` |

`//=` | In-place Integer Division | `x //= 3` | `x = x // 3` |

`**=` | In-place Power | `x **= 3` | `x = x ** 3` |

`&=` | In-place Bitwise And | `x &= 3` | `x = x & 3` |

`|=` | In-place Bitwise Or | `x |= 3` | `x = x | 3` |

`^=` | In-place Bitwise XOR | `x ^= 3` | `x = x ^ 3` |

`>>=` | In-place Bitwise Shift Right | `x >>= 3` | `x = x >> 3` |

<<= | In-place Bitwise Shift Left | `x <<= 5` | `x = x << 5` |

While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.

To help students reach higher levels of Python success, he founded the programming education website Finxter.com that has taught exponential skills to millions of coders worldwide. He’s the author of the best-selling programming books Python One-Liners (NoStarch 2020), The Art of Clean Code (NoStarch 2022), and The Book of Dash (NoStarch 2022). Chris also coauthored the Coffee Break Python series of self-published books. He’s a computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.

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