英文:
kotlin question about distinct by multiple fileds
问题
以下是原始列表：
PersonList: List<Person> = {
Person(id=1, country="US", gender="male")
Person(id=2, country="US", gender="male")
Person(id=3, country="CA", gender="female")
Person(id=4, country="CA", gender="male")
}
结果：按国家和性别去重
结果 ->
listOf(
{country:"US", gender:"male"},
{country:"CA", gender:"female"},
{country:"CA", gender="male"}
)
如何实现这个？
英文:
Here is original list:
PersonList: List<Person> = {
Person(id=1, country="US", gender="male")
Person(id=2, country="US", gender="male")
Person(id=3, country="CA", gender="female")
Person(id=4, country="CA", gender="male")
}
Result: distinct by country & gender
result ->
listOf(
{country:"US", gender:"male"},
{country:"CA", gender:"female"},
{country:"CA", gender:"male"}
)
How can I do this?
答案1
得分: 1
以下是您要翻译的代码部分：
fun main() {
val persons = listOf(
Person(1, "US", "male"),
Person(2, "US", "male"),
Person(3, "CA", "female"),
Person(4, "CA", "male")
)
val result =
persons.distinctBy { it.country to it.gender }.map { mapOf("country" to it.country, "gender" to it.gender) }
println(result)
//[{country=US, gender=male}, {country=CA, gender=female}, {country=CA, gender=male}]
}
data class Person(val id: Int, val country: String, val gender: String)
请注意，我已将 HTML 实体编码解码为原始文本。
英文:
Here's an example of how you could do it:
fun main() {
val persons = listOf(
Person(1, "US", "male"),
Person(2, "US", "male"),
Person(3, "CA", "female"),
Person(4, "CA", "male")
)
val result =
persons.distinctBy { it.country to it.gender }.map { mapOf("country" to it.country, "gender" to it.gender) }
println(result)
//[{country=US, gender=male}, {country=CA, gender=female}, {country=CA, gender=male}]
}
data class Person(val id: Int, val country: String, val gender: String)
</details>
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