17 Creating confusion with octal literals In Go, an integer literal starting with 0 is considered an octal integer (base 8). Note the integer literal representations in Golang: Binary - Uses a 0b or 0B prefix (for example, 0b100 is equal to 4 in base 10) Octal - Uses a 0 or 0o prefix (for example, 0o10 is equal 8 in base 10) Hexadecimal - Uses an 0x or 0X prefix (for example, 0xF is equal to 15 in base 10) Imaginary - Uses an i suffix (for example, 3i) 20 Not understanding slice length and capacity In Go, a slice is backed by an array. That means the slice’s data is stored contiguously in an array data structure. A slice also handles the logic of adding an element if the backing array is full or shrinking the backing array if it’s almost empty. ...

30: Ignoring the fact that elements are copied in range loops type account struct { balance float32 } accounts := []account{ {balance: 100.}, {balance: 200.}, {balance: 300.}, } for _, a := range accounts { a.balance += 1000 } // Output: [{100} {200} {300}] In this example, the range loop does not affect the slice’s content. In Go, everything we assign is a copy: If we assign the result of a function returning a struct, it performs a copy of that struct. If we assign the result of a function returning a pointer, it performs a copy of the memory address (an address is 64 bits long on a 64-bit architecture). Solutions: ...

Using Error Wrapping An error often “bubbles up” a call chain of multiple functions. In other words, a function receives an error and passes it back to its caller through a return value. The caller might do the same, and so on, until a function up the call chain handles or logs the error. An error can be “wrapped” around another error using fmt.Errorf() and the special formatting verb %w. ...

这里简单总结一下三种组合方式: interface 中嵌套 interface struct 中嵌套 struct struct 中嵌套 interface interface 中嵌套 interface 这种组合方式体现了接口隔离原则(ISP)和接口组合原则, 通过接口嵌套，我们可以构建更大的接口 // 基础读接口 type Reader interface { Read(p []byte) (n int, err error) } // 基础写接口 type Writer interface { Write(p []byte) (n int, err error) } // 组合接口 type ReadWriter interface { Reader // 嵌套 Reader 接口 Writer // 嵌套 Writer 接口 } struct 中嵌套 struct 这种组合方式体现了组合优于继承12的原则，是 Go 中实现代码复用的重要方式 // 地址信息 type Address struct { Street string City string Country string } // 用户信息 type User struct { Name string Age int Address // 嵌套 Address struct } // 使用示例 func main() { user := User{ Name: "张三", Age: 25, Address: Address{ Street: "中关村大街", City: "北京", Country: "中国", }, } // 可以直接访问嵌套字段 fmt.Println(user.Street) // 输出: 中关村大街 } struct 中嵌套 interface 这种组合方式体现了依赖倒置原则(DIP)，常用于策略模式的实现 ...

05 Vectors fn array_and_vec() -> ([i32; 4], Vec<i32>) { let a = [10, 20, 30, 40]; // Array // TODO: Create a vector called `v` which contains the exact same elements as in the array `a`. // Use the vector macro. // let v = ??? (a, v) } 这里有几种写法，首先想到的肯定是用一个类似于 for 循环的结构类循环赋值 这里总结一下 Rust 中常见的迭代器 for item in list 会调用 into_iter()，消耗 list 的所有权 for item in &list 会调用 iter()，遍历 list 的引用 for item in &mut list 会调用 iter_mut()，遍历 list 的可变引用 如果想要获取 index, 可以使用 enumerate() 方法: ...