Ruby Array Filter Map

By declan meehan get the most out of ruby by using the select map and reduce methods together image from kgntechnologiesyou should absolutely never ever repeat yourself when writing code.

Ruby array filter map.

If this reasoning makes any sense to anyone else then i believe that the behaviour shown by filter map as is is correct and should be retained. I had a use case to do map on an enumerable with 1 level flattening while skipping nil values. If max min or sort is used the objects in the collection must also implement a meaningful operator as these methods rely on an ordering between members of the collection. In other words do not repeat yourself twice.

Ruby 2 7 has added enumerable filter map as a shorthand for filter map in a single call. The enumerable mixin provides collection classes with several traversal and searching methods and with the ability to sort. To be clear do not write something which has been explained already. But the missing operation was intersection which has another hard to remember short version.

This comes in pretty handy for creating mapped arrays in a simpler way. There are convenient enumerable flat map and enumerable filter map methods but the problem is that they cannot be used at the same time. This is called tautology and when writing code it should be avoided at all times. I had to chose to do either of the following.

In ruby 2 7 this filter map method does this in one pass. Ruby 2 6 introduced array union difference methods to match the more succinct equivalents of array and array. Adding enumerable filter map 78 1 conversation 0 commits 1 checks 0 files changed 4. With rubyconf 2019 behind us and ruby 2 7 releasing this december it s the perfect time to go through what are the new features in the newest 2 x ruby version and also the last release before 3 0.

The class must provide a method each which yields successive members of the collection. I can not say much about array compact but from the name filter map alone i would assume that first a filter is used as a positive select and then the map is applied.