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reactive-programmingreactivex

reactivex repeated skip between

Suppose I have the following stream of data:

1, 2, 3, a, 5, 6, b, 7, 8, a, 10, 11, b, 12, 13, ...

I want to filter everything between 'a' and 'b' (inclusive) no matter how many times they appear. So the result of the above would be:

1, 2, 3, 7, 8, 12, 13, ...

How can I do this with ReactiveX?

Solution

  • Use scan with initial value b to turn

    1, 2, 3, a, 5, 6, b, 7, 8, a, 10, 11, b, 12, 13, ...

    into

    b, 1, 2, 3, a, a, a, b, 7, 8, a, a, a, b, 12, 13, ...

    and then filter out a and b to get

    1, 2, 3, 7, 8, 12, 13, ...

    In pseudo code

    values.scan('b', (s, v) -> if (v == 'a' || v == 'b' || s != 'a') v else s). filter(v -> v != 'a' && v != 'b');