python - ast.literal_eval 调用中格式错误的节点

Question

据我了解，ast.literal_eval 适用于文字，那么为什么这会给我一个错误？

import ast

ast.literal_eval("1+2")

错误:

Traceback (most recent call last):
  File "/snap/pycharm-community/355/plugins/python-ce/helpers/pydev/pydevd.py", line 1500, in _exec
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File "/snap/pycharm-community/355/plugins/python-ce/helpers/pydev/_pydev_imps/_pydev_execfile.py", line 18, in execfile
    exec(compile(contents+"\n", file, 'exec'), glob, loc)
  File "/home/home-pc/.config/JetBrains/PyCharmCE2023.2/scratches/scratch.py", line 3, in <module>
    ast.literal_eval("(1+2)")
  File "/usr/lib/python3.10/ast.py", line 110, in literal_eval
    return _convert(node_or_string)
  File "/usr/lib/python3.10/ast.py", line 109, in _convert
    return _convert_signed_num(node)
  File "/usr/lib/python3.10/ast.py", line 83, in _convert_signed_num
    return _convert_num(node)
  File "/usr/lib/python3.10/ast.py", line 74, in _convert_num
    _raise_malformed_node(node)
  File "/usr/lib/python3.10/ast.py", line 71, in _raise_malformed_node
    raise ValueError(msg + f': {node!r}')
ValueError: malformed node or string on line 1: <ast.BinOp object at 0x7f85e1b73a00>
python-BaseException

Answer 1

在 ast.literal_eval() 中，+ 运算符仅适用于从 Python 3.7 开始的复数，请参阅:

• 问题:https://github.com/python/cpython/issues/75959
• 修复提交:https://github.com/python/cpython/commit/d8ac4d1d5ac256ebf3d8d38c226049abec82a2a0

(换句话说，它确实与其他表达式一起工作的事实是一个错误。)

您可能想要例如https://github.com/valohai/leval (免责声明:我的代码)或 https://pypi.org/project/pure-eval/相反。