On 9/9/22 04:15, Warren Weckesser wrote:
...
To quote from https://docs.python.org/3/library/functions.html#repr:

For many types, this function makes an attempt to return a string
that would yield an object with the same value when passed to eval();
Sebastian, is this an explicit goal of the change?  (Personally, I've
gotten used to not taking this too seriously, but my world view is
biased by the long-term use of NumPy, which has never followed this
guideline.)

If that is a goal, than the floating point types with precision
greater than double precision will need to display the argument of the
type as a string.  For example, the following is run on a platform
where numpy.longdouble is extended precision (80 bits):

```
In [161]: longpi = np.longdouble('3.14159265358979323846')

In [162]: longpi
Out[162]: 3.1415926535897932385

In [163]: np.longdouble(3.1415926535897932385)  # Argument is parsed
as 64 bit float
Out[163]: 3.141592653589793116

In [164]: np.longdouble('3.1415926535897932385')  # Correctly
reproduces the longdouble
Out[164]: 3.1415926535897932385
```

Warren


As others have mentioned, the change will greatly enhance UX at the cost of documentation cleanups. While the representation may not be perfectly roundtrip-able, I think it still is an improvement and worthwhile. Elsewhere I have suggested we need more documentation around array/scalar printing, perhaps that would be a place to mention the limitations of string representations.

Matti

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