Hey how can I write same in kotlin of that swift code ```if kotlinlang #announcements

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Title

Nicolas Chaduc

05/25/2018, 7:51 AM

Hey, how can I write same in kotlin of that swift code :

if let valueCatchNotNull = valueCanBeNull {
} else {
}

we can catch value not null with

?.let

but can’t use else

Olivier Patry

05/25/2018, 7:53 AM

valueCatchNotNull?. let {
  <if not null part>
} ?: <else part>

marstran

05/25/2018, 7:54 AM

This will execute the else part if the "if not null" part returns null.

👍 1

gildor

05/27/2018, 9:58 AM

In many cases smart cast can help without additional ceremony:

if (valueCanBeNull != null) {
   //Cannot be null anymore
} else {
  // Is actually null
}

If smart cast doesn't work for you case (for example you value is mutable nullable of class level or from some third party code, I would prefer just to assign it to local variable and use smart cast like on my previous sample:

val someNullable = someCode.someNullable
if (someNullable != null) {
 // Now smart cast works
}

This common if looks much better for me than really messy let + run

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