Kotlin coroutine flow, firstOrNull only needs to be first, lastOrNull only needs to be last

Kotlin coroutine flow, firstOrNull only needs to be first, lastOrNull only needs to be last

 

        <!-- https://mvnrepository.com/artifact/org.jetbrains.kotlinx/kotlinx-coroutines-core -->
        <dependency>
            <groupId>org.jetbrains.kotlinx</groupId>
            <artifactId>kotlinx-coroutines-core</artifactId>
            <version>1.7.3</version>
            <type>pom</type>
        </dependency>

 

import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.*
import kotlinx.coroutines.runBlocking

fun main(args: Array<String>) {
    runBlocking {
        val firstResult = load()
            .firstOrNull() //虽然发射很多数据，但只要第1次发射过来的数据。
        println(firstResult)

        val lasResult = load()
            .lastOrNull() //虽然发射很多数据，但只要最后1次发射过来的数据。
        println(lasResult)
    }
}

fun load() = flow {
    for (i in 1..5) {
        emit(i)
        delay(10)
    }
}

 

 

 

 

 

 

 

 

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