Kotlin协程flow，firstOrNull只要最先first，lastOrNull只要最后

爱被打了一巴掌 2023-10-15 10:18 44阅读 0赞

### Kotlin协程flow，firstOrNull只要最先first，lastOrNull只要最后 ###

###  ###

<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)
        }
    }

![f66a04c0c41e46b0b8d0cec959067e90.png][]

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