ENH: Interval.__contains__(self, other: Interval)

[choucavalier]

Is your feature request related to a problem?

Not a problem. Just a feature I would have liked to have! :-)

I would like to be able to know if an Interval is contained into another Interval.

e.g. [2, 3) is contained in [2, 4) but not in (2, 4]

Describe the solution you'd like

Something like this

def interval_contains(a: pd.Interval, b: pd.Interval) -> bool:
    res = a.left <= b.left and a.right >= b.right
    if a.open_left and b.closed_left:
        res &= a.left < b.left
    if a.open_right and b.closed_right:
        res &= a.right > b.right
    return res

API breaking implications

Currently, if you do something like this

a = pd.Interval(2, 3, closed="left")
b = pd.Interval(2, 4, closed="left")
print(a in b)

it raises the following exception

TypeError: __contains__ not defined for two intervals

Adding support for another type of object in __contains__ would not break the API, but just extend it.

Describe alternatives you've considered

Could not find any.

[jreback]

https://pandas.pydata.org/docs/reference/api/pandas.IntervalIndex.contains.html?highlight=contains#pandas.IntervalIndex.contains

[choucavalier]

@jreback thanks for your reply. I know about what you just referred to. It works with scalar values but it does not work with another Interval. Therefore, I am not sure how your answer is relevant to the original feature request.

[samukweku]

@tgy is this similar to interval overlap? Maybe interval overlaps could apply

[choucavalier]

@tgy is this similar to interval overlap? Maybe interval overlaps could apply

Thanks for your reply. I know about the overlaps() method of Interval, as I read the documentation and the code before opening this issue.

Interval containment is different from interval overlap.

First of all, the overlaps operator is commutative. In other words, for any given two intervals a and b, we have that a.overlaps(b) iff b.overlaps(a). This is not the case with the containment operator: if a is contained in b, then b is not necessarily contained in a (the latter is true iff b = a).

This simple observation is already enough to understand that these two operators are different. But let's take a concrete example as well.

The two intervals a = [2, 4) and b = (2, 5] overlap but neither a contains b nor b contains a.

[venaturum]

You can find this functionality in piso until it is implemented in pandas

https://piso.readthedocs.io/en/latest/reference/api/piso.interval.issuperset.html#piso.interval.issuperset

[choucavalier]

ah thanks @venaturum! that package fell under my radar. interesting.

[kapiliyer]

take