Make "X | Y" union syntax more prominent in documentation #17835
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Soon 4 out of 5 supported Python versions will support the `X | Y` syntax, so we can make it more prominent (Python 3.13 will be out soon, and 3.8 will reach end of life). The syntax is available starting from Python 3.10, but it can be used in annotations in earlier Python versions as well if using `from __future__ import annotations`.
JelleZijlstra
approved these changes
Sep 26, 2024
docs/source/kinds_of_types.rst
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| @@ -236,18 +237,16 @@ Python functions often accept values of two or more different | |||
| types. You can use :ref:`overloading <function-overloading>` to | |||
| represent this, but union types are often more convenient. | |||
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| Use the ``Union[T1, ..., Tn]`` type constructor to construct a union | |||
| type. For example, if an argument has type ``Union[int, str]``, both | |||
| Use the ``T1 | ... | Tn`` type constructor to construct a union | |||
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Suggested change
| Use the ``T1 | ... | Tn`` type constructor to construct a union | |
| Use the ``T1 | ... | Tn`` operator to construct a union |
Feels odd to call this a "type constructor"
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Using "operator" here also didn't feel quite right, so I just left out the "type constructor" bit.
docs/source/kinds_of_types.rst
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| t1: int | str # equivalent to Union[int, str] | ||
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| t2: int | None # equivalent to Optional[int] | ||
| The type ``... | None`` *does not* mean a function parameter with a default value. |
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Since this confusion is related to the name Optional, it might be better to keep using Optional[T] here.
Co-authored-by: Brian Schubert <brianm.schubert@gmail.com> Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
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Soon 4 out of 5 supported Python versions will support the
X | Ysyntax,so we can make it more prominent (Python 3.13 will be out soon, and 3.8
will reach end of life). Use it in most examples.
The syntax is available starting from Python 3.10, but it can be used
in annotations in earlier Python versions as well if using
from __future__ import annotations.