Go基础知识学习1
输入代码
package main
import (
"fmt"
)
func main() {
//Println Printf
fmt.Println("Golang, I am Michael.Pan!")
i := 101
fmt.Printf("i = %v \n", i)
//var int string bool
var cnt = 100
str := "hangzhou,China"
substr := str[1:]
var isSuccess = true
fmt.Printf("cnt = %v str = %v substr= %v isSuccess = %v \n", cnt, str, substr, isSuccess)
//Const
const MAXCOUNT = 30
const NAME = "China"
fmt.Printf("MAXCOUNT = %v , NAME = %v\n", MAXCOUNT, NAME)
//calc and var +
var j = 101
var k int
k = j + 19
fmt.Printf("k = %v \n", k)
//array
var a [10]int
a[0] = 10
a[1] = 11
fmt.Printf("a = %v \n", a)
// array foreach
for index, value := range a {
fmt.Printf("index = %v, value = %v\n", index, value)
}
//slice add remove
b := []int{1, 2, 3, 4, 5, 6}
b = append(b, 7, 8, 9, 10, 11, 12)
c := make([]int, 10, 20)
copy(c, b)
fmt.Printf("b = %v \nc = %v len(c) = %v cap(c) = %v\n", b, c, len(c), cap(c))
//slice foreach
for index, value := range c {
fmt.Printf("index = %v, value = %v\n", index, value)
}
//map
m := make(map[string]string)
m["a"] = "China"
m["b"] = "American"
m["c"] = "Brizer"
m["d"] = "Japan"
fmt.Printf("m(1) = %v\n", m)
delete(m, "c")
fmt.Printf("m(2) = %v\n", m)
value1, ok1 := m["c"]
fmt.Printf("value1 = %v ok1 = %v\n", value1, ok1)
value2, ok2 := m["d"]
fmt.Printf("value2 = %v ok2 = %v\n", value2, ok2)
for key, value := range m {
fmt.Printf("key = %v value = %v\n", key, value)
}
//for exp1,2,3
fmt.Printf("sum1 = %v,sum2 = %v,sum3 = %v\n", sum1(), sum2(), sum3())
//switch
fmt.Printf("str0 = %v\n", getStr(0))
fmt.Printf("str1 = %v\n", getStr(1))
fmt.Printf("str2 = %v\n", getStr(2))
fmt.Printf("str3 = %v\n", getStr(3))
fmt.Printf("str4 = %v\n", getStr(4))
fmt.Printf("str5 = %v\n", getStr(5))
fmt.Printf("str6 = %v\n", getStr(6))
fmt.Printf("str6 = %v\n", getStr(100000))
// slice append
arr := []int{1, 2, 3, 4, 5}
slice := arr[1:2]
slice = append(slice, 6, 7, 8)
fmt.Println(slice)
fmt.Println(arr)
// function
fmt.Println(quicksum1(11, 12))
fmt.Println(quicksum2(1, 2, 3, 4, 5, 6))
// callback
fmt.Println(quickcmp(10, 12, compare))
fmt.Println(quickcmp(32, 12, compare))
fmt.Println(quickcmp(12, 12, compare))
//closure
f1 := plus(10)
f2 := plus(15)
fmt.Println(f1(20))
fmt.Println(f2(25))
}
func sum1() int {
sum := 0
for i := 0; i < 10; i++ {
sum += i
}
return sum
}
func sum2() int {
sum := 0
i := 0
for i < 10 {
sum += i
i++
}
return sum
}
func sum3() int {
sum := 0
i := 0
for {
sum += i
i++
if i == 10 {
break
}
}
return sum
}
func getStr(a int) string {
var str string
switch a {
case 0:
str = "China"
case 1:
str = "American"
case 2, 3, 4, 5:
str = "Japan"
default:
str = "others"
}
return str
}
func quicksum1(a int, b int) (sum int) {
sum = a + b
return
}
func quicksum2(a ...int) (sum int) {
for _, value := range a {
sum += value
}
return
}
func compare(a int, b int) int {
if a > b {
return 1
} else if a == b {
return 0
} else {
return -1
}
}
func quickcmp(a int, b int, f func(int, int) int) (result int) {
result = f(a, b)
return
}
func plus(a int) func(b int) int {
return func(b int) int {
return a + b
}
}
输出结果
Golang, I am Michael.Pan!
i = 101
cnt = 100 str = hangzhou,China substr= angzhou,China isSuccess = true
MAXCOUNT = 30 , NAME = China
k = 120
a = [10 11 0 0 0 0 0 0 0 0]
index = 0, value = 10
index = 1, value = 11
index = 2, value = 0
index = 3, value = 0
index = 4, value = 0
index = 5, value = 0
index = 6, value = 0
index = 7, value = 0
index = 8, value = 0
index = 9, value = 0
b = [1 2 3 4 5 6 7 8 9 10 11 12]
c = [1 2 3 4 5 6 7 8 9 10] len(c) = 10 cap(c) = 20
index = 0, value = 1
index = 1, value = 2
index = 2, value = 3
index = 3, value = 4
index = 4, value = 5
index = 5, value = 6
index = 6, value = 7
index = 7, value = 8
index = 8, value = 9
index = 9, value = 10
m(1) = map[a:China b:American c:Brizer d:Japan]
m(2) = map[a:China b:American d:Japan]
value1 = ok1 = false
value2 = Japan ok2 = true
key = a value = China
key = b value = American
key = d value = Japan
sum1 = 45,sum2 = 45,sum3 = 45
str0 = China
str1 = American
str2 = Japan
str3 = Japan
str4 = Japan
str5 = Japan
str6 = others
str6 = others
[2 6 7 8]
[1 2 6 7 8]
23
21
-1
1
0
30
40
参考文献
- 基础知识参考：学习GO语言.pdf 作者：Miek Gieben 翻译：邢兴
- 闭包参考：http://www.cnblogs.com/Jifangliang/archive/2008/08/05/1260602.html
- 闭包参考：http://golang.org/doc/articles/wiki/