Maybe a basic question, but I want to filter a lis...

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[crummy]

Maybe a basic question, but I want to filter a list, call a function with each matching element, then collate the results to a new list. Is there a more elegant way than this:

val filtered = all.filter { it.foo }
   .map {
      callFunction(it)
      return it
   }.toList()

[gildor]

this looks as wrong snippet

[gildor]

return it doesn’t work in lambda, it returns from enclosing function

[gildor]

Also toList() is useless in this case

[gildor]

and for side efects you can use onEach

[gildor]

val filtered = all.filter { it.foo }
.onEach {
callFunction(it)
}

[crummy]

onEach - that's what I was looking for!

[crummy]

thanks

[gildor]

But I would just split this:

val filtered = all.filter { it.foo }
filtered.forEach { callFunction(it) }

[gildor]

because I don’t see for this particular snippet reason to combine these operations in a single chain if callFunction doesn’t modify it

[crummy]

for readability?

[gildor]

also you can use method reference:

onEach(::callFunction)

[gildor]

to be more explicit, if I have chain I usually expect that each operator somehow modifies it

[gildor]

but in this case it’s just side effect

[gildor]

anyway forEach has good use cases, such as logging

[gildor]

so I wouldn’t say that splitting is always better, depends on use case and context

[crummy]

ok, thanks for all the info.