Programming/Kotlin

[Kotlin] object list ์—์„œ ํŠน์ • ํ•„๋“œ ๊ฐ’ (field value) ๊ฐ€์ ธ์˜ค๋Š” ๋ฐฉ๋ฒ•

yuri lee 2023. 1. 7. 16:19
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Intro 

์•ˆ๋…•ํ•˜์„ธ์š”. ์ด๋ฒˆ ์‹œ๊ฐ„์—๋Š” object list์—์„œ ๋‹จ์ผ field ๊ฐ’์„ ๊ฐ€์ ธ์˜ค๋Š” ๋ฐฉ๋ฒ•์— ๋Œ€ํ•ด ์•Œ์•„๋ณด๋„๋ก ํ•˜๊ฒ ์Šต๋‹ˆ๋‹ค. ์˜ˆ๋ฅผ ๋“ค์–ด ์•„๋ž˜์™€ ๊ฐ™์€ ์ฝ”ํ‹€๋ฆฐ ์ฝ”๋“œ๊ฐ€ ์žˆ๋‹ค๊ณ  ๊ฐ€์ •ํ•ด๋ด…์‹œ๋‹ค. ์—ฌ๊ธฐ์„œ { "hong", "kil" } ์™€ ๊ฐ™์€ ํ˜•์‹์œผ๋กœ ๋‹จ์ผ ํ•„๋“œ ๊ฐ’๋งŒ ๊ฐ€์ ธ์˜ค๊ณ  ์‹ถ์œผ๋ฉด ์–ด๋–ป๊ฒŒ ํ•ด์•ผ ํ• ๊นŒ์š”? 

fun main(args:Array<String>){
    println("Hello World")
    val list = listOf(member("hong",10), member("kil", 10))
}

data class member(var name:String, var age:Int)

 

How to solve the problem

์•„๋ž˜์™€ ๊ฐ™์ด ๊ฐ„๋‹จํ•˜๊ฒŒ map() ๋ฉ”์†Œ๋“œ๋ฅผ ํ†ตํ•˜์—ฌ name์ด๋ผ๋Š” ํ•„๋“œ๋งŒ ๊ฐ€์ ธ์˜ฌ ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค. 

val names = list.map { it.name }

 

 


https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/map.html

https://stackoverflow.com/questions/50603424/how-to-get-single-field-value-in-object-list

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