Search code examples
pythonpython-3.xoperatorsmatrix-multiplicationpython-3.5

What is the '@=' symbol for in Python?

I know @ is for decorators, but what is @= for in Python? Is it just reservation for some future idea?

This is just one of my many questions while reading tokenizer.py.

Solution

  • From the documentation:

    The @ (at) operator is intended to be used for matrix multiplication. No builtin Python types implement this operator.

    The @ operator was introduced in Python 3.5. @= is matrix multiplication followed by assignment, as you would expect. They map to __matmul__, __rmatmul__ or __imatmul__ similar to how + and += map to __add__, __radd__ or __iadd__.

    The operator and the rationale behind it are discussed in detail in PEP 465.