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crystal-lang

Type-safe way to remove nulls from Array in Crystal

Is there a preferred and type-safe way without forced typecast to remove nils from Array? 

[1, nil].select{|x| !!x}
// => Array(Int32 | Nil)

Something like special select?

P.S.

The use case when I hit this issue - I want to calculate median and the sort won't work:

[1, nil].select{|x| !!x}.sort

Map with zeros [1, nil].map{|x| x || 0} won't work as unlike let's say sum for some operations the length does matter (median for example).

Solution

  • Array#compact will remove nils from the Array:

    [1, nil].compact # => [1] (Array(Int32))