Dtype strict mode

[sinhrks]

pandas dtype coercion is useful in most cases, but there are situations to prohibit it to avoid unexpected values being included. The behavior should be switchable like:

s = pd.Series([1, 2, 3])
s[1] = 1.2
s
#0    1
#1    1
#2    3
# dtype: int64

s[1] = 'x'
s
#0    1
#1    x
#2    3
# dtype: object

s = pd.Series([1, 2, 3], cast=False)
s[1] = 'x'
TypeError...

[max-sixty]

Strict immutability is another potential option

[shoyer]

I agree with @MaximilianR, though I'm not sure if he meant immutable dtypes or immutable values altogether!

In any case, dtype coercion is certainly a feature that I would gladly drop altogether.

[max-sixty]

immutable dtypes or immutable values

Immutable dtypes is the lower hanging fruit! But now you mention immutable values...

[wesm]

The implicit casting behavior that exists now (really just to permit nulls to be inserted into dtypes that don't support them) makes me super uncomfortable. I guess I would need to understand more use cases as adding the flexibility would be quite a bit of work.