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

python python-3.x operators matrix-multiplication python-3.5
Octavia Togami picture Octavia Togami · Dec 9, 2014 · Viewed 41.8k times · Source

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.

Answer

rightfold picture rightfold · Dec 9, 2014

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.

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