Python中eval()和print()函数中的错误

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Python中eval()和print()函数中的错误

该问题已经有答案了:

为什么print函数返回None？

我试图在Python IDLE中运行以下代码:

>>> eval(print("123*13"))

我得到了正确的输出，但是它也伴随着一个TypeError：

123*13
Traceback (most recent call last):
  File "<pyshell#4>", line 1, in 
    eval(print("123*13"))
TypeError: eval() arg 1 must be a string, bytes or code object

注意：

我不想使用print(eval(\"123*13\"))。

我想在eval()函数中使用print()。

这不是一个实际的实现问题，但是在使用eval()函数时我会遇到这个错误。我提出这个问题只是好奇而已。

admin 更改状态以发布 2023年5月21日
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1 答案

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使用方法:

eval('print("123*13")')

在eval()函数的src中:

evel (__source: str | bytes | CodeType, __globals: Dict[str, Any] | None = ..., __locals: Mapping[str, Any] | None = ...) -> Any
'''Evaluate the given source in the context of globals and locals.
The source may be a string representing a Python expression    
or a code object as returned by compile().
The globals must be a dictionary and locals can be any mapping,
defaulting to the current globals and locals.
If only globals is given, locals defaults to it.'''
...

eval函数帮助文档:

eval(source, globals=None, locals=None, /)
    Evaluate the given source in the context of globals and locals.
    The source may be a string representing a Python expression
    or a code object as returned by compile().
    The globals must be a dictionary and locals can be any mapping,
    defaulting to the current globals and locals.
    If only globals is given, locals defaults to it.

你可以在Python.org中查看更多资料。

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