Hey, could anyone help me with something? with th...

# getting-started

[li-s]

Hey,
could anyone help me with something?

with the data class below:

data class Item(val completed: Boolean, val details: String? = null)

and a list:

val p = listOf(
        Item(true, "one"),
        Item(false, "two"),
        Item(true, "three")
	)

I need to transform this data (truncate the second value in the Item to return something like:

listOf(
        Item(true, "o"),
        Item(false, "t"),
        Item(true, "t")
	)

Im trying:

val p = listOf(
        Item(true, "one"),
        Item(false, "two"),
        Item(true, "three")
	)
    
    println(p.map { (_,details) -> details?.take(1) })

but it returns: [o, t, t]

What’s the best way to do this in Kotlin?
Thank you in advance

[allan.conda]

how about

item -> item.copy(details = item.details?.take(1))

[li-s]

huh

[li-s]

thanks so much

[Michael de Kaste]

the fact that you said huh means there is a need for an explanation

[Michael de Kaste]

The dataclasses you showed are immutable (you provided val ). This means that whatever input you show, for them you need to recreate the entire dataclass if you want it's data to be modified.

item -> item.copy(details = item.details?.take(1))

is the same as:

item -> Item(item.completed, item.details?.take(1))

as in, you are creating a new item, with modified data