Python object.__repr__(self) should be an expression?

Question

I was looking at the builtin object methods in the Python documentation, and I was interested in the documentation for `object.__repr__(self)`. Here's what it says: Called by the repr() built-in function and by string conversions (reverse quotes) to compute the “official” string representation of an object. If at all possible, this should look like a valid Python expression that could be used to recreate an object with the same value (given an appropriate environment). If this is not possible, a string of the form <...some useful description...> should be returned. The return value must be a string object. If a class defines repr() but not str(), then repr() is also used when an “informal” string representation of instances of that class is required. This is typically used for debugging, so it is important that the representation is information-rich and unambiguous The most interesting part to me, was... If at all possible, this should look like a valid Python expression that could be…

Accepted Answer

```
>>> from datetime import date
>>>
>>> repr(date.today())        # calls date.today().__repr__()
'datetime.date(2009, 1, 16)'
>>> eval(_)                   # _ is the output of the last command
datetime.date(2009, 1, 16)
```

The output is a string that can be parsed by the python interpreter and results in an equal object.

If that's not possible, it should return a string in the form of `<...some useful description...>`.

Python object.repr(self) should be an expression?

Solution

Problem