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macos install 2.7 brew install openssl openssl@1.1 readline sqlite3 xz zlib pyenv export LDFLAGS="-L/opt/homebrew/opt/openssl@1.1/lib" export CPPFLAGS="-I/opt/homebrew/opt/openssl@1.1/include" pyenv install 2.7.18 Reference

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Java to Kotlin migration guides String 连接字符串: Java: “1” + “b” kotlin: “$a$b” 生成字符串: Java: StringBuilder kotlin: buildString() // 底层也是使用StringBuilder 通过集合创建字符串: Java: Stream API // Java List numbers = List.of(1, 2, 3, 4, 5, 6); String invertedOddNumbers = numbers .stream() ...

kotlin jvm kotlin多平台开发支持: Android and iOS (在Alpha阶段) JVM JavaScript Native Scripting Comparison to java Some Java issues addressed in Kotlin: Null references are controlled by the type system. No raw types Arrays in Kotlin are invariant Kotlin has proper function types, as op...

kotlin reflection dependencies { implementation("org.jetbrains.kotlin:kotlin-reflect:1.7.20") } <dependencies> <dependency> <groupId>org.jetbrains.kotlin</groupId> <artifactId>kotlin-reflect</artifactId> </dependency> </dependencies> references class references ...

kotlin destructuring declarations val (name, age) = person 被翻译成: val name = person.component1() val age = person.component2() for ((a, b) in collection) { ... } Reference

kotlin this To denote the current receiver, you use this expressions: * In a member of a class, this refers to the current object of that class. * In an extension function or a function literal with receiver this denotes the receiver parameter that is passed on the left-hand side of a dot. If this has no qualifiers, it refers to the innermo...

kotlin null safety kotlin中产生NPE的原因: * 显示调用throw NullPointerException() * 使用!!调用null引用 * 使用未正确初始化的引用 - a leaking this - 超类构造函数中使用在子类初始化的open member * Java集成 - 访问null引用 - java把null添加到kotlin MutableList - 由外部java 代码 避免使用null: 1. 显示使用if检查null, 变量需要是不可变的(保证使用时变量值不是null), 编译器会跟踪检查信息. ...