Go常见

GO基础语法

1. 方法或函数调用时，传入参数一般都是值复制，除非是map、slice、channel、指针类型是引用传递

2. 短的变量声明（Short Variable Declarations），即自动推导，只能在函数内部使用

3. 字符串与[]byte之间的转换是复制（有内存消耗），使用range来避免内存分配来提高性能

4. 使用for range迭代map时每次迭代的顺序可能不一样，map的迭代事随机的

5. switch case匹配case条件后默认退出，除非使用fallthrough继续匹配

6. 没有前置自增、前置自减

7. 位运算优先级高于四则运算

8. log包中的log.Fatal和log.Panic不仅仅记录在日志，还会终止程序

9. nil只能赋值给指针、channel、func、interface、map或slice类型的变量

10. make和new的区别

    1. make只能用于slice、map、channel的初始化，它返回的类型就是这三个类型的本身，而不是他们的指针类型，因为这三种类型就是引用类型。分配空间并初始化。

       // The make built-in function allocates and initializes an object of type
       // slice, map, or chan (only). Like new, the first argument is a type, not a
       // value. Unlike new, make's return type is the same as the type of its
       // argument, not a pointer to it. The specification of the result depends on
       // the type:
       //	Slice: The size specifies the length. The capacity of the slice is
       //	equal to its length. A second integer argument may be provided to
       //	specify a different capacity; it must be no smaller than the
       //	length. For example, make([]int, 0, 10) allocates an underlying array
       //	of size 10 and returns a slice of length 0 and capacity 10 that is
       //	backed by this underlying array.
       //	Map: An empty map is allocated with enough space to hold the
       //	specified number of elements. The size may be omitted, in which case
       //	a small starting size is allocated.
       //	Channel: The channel's buffer is initialized with the specified
       //	buffer capacity. If zero, or the size is omitted, the channel is
       //	unbuffered.
       func make(t Type, size ...IntegerType) Type
       

    2. new只接受一个参数，这个参数是一个类型，返回一个指向该类型内存地址的指针，同时把分配的内存置为零。new不仅能够为系统默认的数据类型分配空间，也能为自定义类型分配空间

       // The new built-in function allocates memory. The first argument is a type,
       // not a value, and the value returned is a pointer to a newly
       // allocated zero value of that type.
       func new(Type) *Type
       

11. 常量无法寻址，不能进行取指针操作操作