kotlin-fundamentals

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Original

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Master Kotlin programming fundamentals with production-ready patterns.

掌握具备生产就绪模式的Kotlin编程基础。

kotlin

// Safe call + Elvis
val name = user?.name ?: "Anonymous"

// requireNotNull for validation
requireNotNull(user) { "User required" }

kotlin

// 安全调用 + Elvis运算符
val name = user?.name ?: "Anonymous"

// 使用requireNotNull进行验证
requireNotNull(user) { "User required" }

kotlin

data class User(val id: Long, val name: String) {
    init { require(name.isNotBlank()) }
}

kotlin

data class User(val id: Long, val name: String) {
    init { require(name.isNotBlank()) }
}

Function	Context	Returns	Use Case
`let`	it	Lambda result	Null-safe transforms
`apply`	this	Same object	Object configuration
`run`	this	Lambda result	Object scope + result
`also`	it	Same object	Side effects

Issue	Resolution
NPE despite null check	Check platform types from Java
Smart cast fails	Use local variable or let

问题	解决方法
即使进行了空检查仍出现NPE	检查来自Java的平台类型
智能转换失败	使用局部变量或let函数

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Skill("kotlin-fundamentals")