filter(): %in% %notin% | & operators and slice() operation

Hey @machow , I hope you are doing well.

I have some questions and suggestions regarding filter() that I would like to discuss here if I may.

(1) Enable logical operators &, |, or and, or inside filter(). Right now I could not find a way to use or logic, for example: filter(_.x>2 | ._x==0.5)

(2) Would you consider implementing %in% (and %notin%) operators to do something like filter(_.country %in% ['Australia', 'Ireland']) ? Currently we have to rely on pandas syntax filter(_.country.isin(["Australia","Ireland"])

(3) Since siuba currently does not have slice(), is there an easy way to accomplish the same task using filter()?

Thank you

[ghost]

The in operator relies on the __contains__(a, b) method being defined for the object on the right-hand side. This means that you would need to create a siuba aware wrapper class for sequences.

The wrapper would define the __contains__(a, b) method.

class SiubaSequenceWrapper:
    def __init__(self, value):
        self.value = value
    def __contains__(self, other):
        return other.isin(self.value)

The final syntax would be:

filter(_.country in SiubaSequenceWrapper(['Australia', 'Ireland']))

I’m sure you can think of a better name for the wrapper… (This is how you can do it. I don’t know if you should do it!)

[machow]

@davidwales unfortunately the __contains__ method requires that you return a Boolean 😕. AFAIK siuba’s symbolic class can’t handle __iter__, __contains__, or the keywords and, or (these keywords throw errors for pandas and bumpy arrays too for the same reason).