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Hello people, is there a way to “merge” 2 validated?
E.g. given two `Validated&lt;A, B&gt;` , if they were `Either` I would do, for example
```either {
  val a = eitherA.bind()
  val b = eitherB.bind()
  Combine(a, b)
}```
What’s the right way to do it with `Validated`? Either with the `either` block or any other solution :slightly_smiling_face:

You would normally use the `zip` extension for this but you'd need to provide some way of merging `A` in case both were invalid. Usually this is covered by using `ValidatedNel&lt;A, B&gt;` (a typealias for `Validated&lt;NonEmptyList&lt;A&gt;, B&gt;`)

Thank you for the answer.
Could you please provide a real example, considering two `Validated&lt;String, Int&gt;` ? :slightly_smiling_face:

I’m not very familiar with different types than `Either` , so I’m struggling to understand how to use it

How would you want to merge the two error Strings?

Or just provide an example with the `ValidateddNel` , I just need an example of how to use `zip` , then I’ll take it from there :slightly_smiling_face:

Regarding that, with Arrow 1.2.x onwards, `Validated` is going to be deprecated, and removed from Arrow 2.0.0 to simplify this.

For `ValidatedNel` it's relatively simple to use `.validNel()` and `.invalidNel()`  to construct your values much like you would `.valid()` and `.invalid()`. Once you have two values you can join them using  `a.zip(b) { validA, validB -&gt; doSomethingWith(validA, validB) }`

With 1.2.x and above there'll be an `zipOrAccumulate` set of functions that will provide the same logic (combining one or more lefts, or providing all rights to a function)

With `ValidatedNel` I felt less stupid and everything worked straight away :slightly_smiling_face:

With `Validated&lt;A, B&gt;` you need to provide an additional argument to zip of a `Semigroup&lt;A&gt;` (which is effectively just a function `A.(A) -&gt; A`  like `String::plus` )

With a custom combine to comma-delimit errors you can have
```lateinit var a: Validated&lt;String, Int&gt;
lateinit var b: Validated&lt;String, Int&gt;

fun String.combine(other: String) = "$this, $other"

a.zip(String::combine, b) { validA, validB -&gt; validA + validB }```