A Tour of Go: Basics 1
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Packages, variables and functions
Packages
packages中，以大写字母开头的name是exported name，当import package时，只有exported name可以被从外部访问。
Functions
同type的连续参数可以只在最后指明type。
函数可以有多个返回值。
func swap(x, y string) (string, string) {
return y, x
}
Go支持有name的返回值：
- 函数定义时就定义好返回变量名，在函数内操作返回变量。
- 用naked return语句返回。
func split(sum int) (x, y int) {
x = sum * 4 / 9
y = sum - x
return
}
注意点：文中建议只在短函数中这样使用，因为长了容易影响可读性。
Variables
var关键字定义变量。
有初始值时可以省略type。
技巧及注意点：
- 在函数内，可以使用:=符号替换有初始值的变量定义。
- 但是在函数外，所有语句必须以关键字开始，所以不能使用:=符号。
Basic types
bool
string
int int8 int16 int32 int64
uint uint8 uint16 uint32 uint64 uintptr
byte // alias for uint8
rune // alias for int32
// represents a Unicode code point
float32 float64
complex64 complex128
技巧：
- var和import都可以用小括号声明多个包或变量。
- 文中建议，如无特殊需求，使用int就好，不必指明size或sign。
变量定义时，如不指定初始值，则分配对应type的默认值。
- numeric type: 0
- bool: false
- string: ""
表达式T(v)表示将值v转换成T类型：
var i = 10 var f = float64(i)
注意点：与C语言不同，Go必须显式转换。
常量定义将var换成const关键字即可，不过不能使用:=符号。
疑问
- Numeric constants are high-precision values.
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