From: acevest <zhaoyanbai@126.com>
Date: Sat, 28 Nov 2015 12:21:07 +0000 (+0800)
Subject: learn go ...
X-Git-Url: http://zhaoyanbai.com/repos/readme1st.txt?a=commitdiff_plain;h=c45ae8812750d939f259ff1693e39db48ac280cf;p=acecode.git

learn go ...
---

diff --git a/learn/go/array.slice.map.go b/learn/go/array.slice.map.go
index 2c2cdeb..410fd6f 100644
--- a/learn/go/array.slice.map.go
+++ b/learn/go/array.slice.map.go
@@ -1,6 +1,7 @@
 package main
 
 import "fmt"
+import "math/rand"
 
 type Vector struct {
 	x, y uint32
@@ -54,6 +55,10 @@ func main() {
 	e = append(e, "append:d")
 	e = append(e, "append:e", "append:f")
 
+	// 切片复制
+	var f []string
+	copy(f, e)
+
 	for i := 0; i < len(e); i++ {
 		fmt.Println(e[i])
 	}
@@ -76,7 +81,7 @@ func main() {
 	if Map == nil {
 		fmt.Println("Map is nil")
 	}
-	Map = make(map[string]Vector)
+	Map = make(map[string]Vector, 100)
 	if Map == nil {
 		fmt.Println("Map is nil")
 	} else {
@@ -107,21 +112,76 @@ func main() {
 	MapA["Test"] = "USA"
 	fmt.Println(MapA)
 
-	var s string
-	var ok bool
-	s, ok = MapA["Test"]
-	if !ok {
+	if s, ok := MapA["Test"]; !ok {
 		fmt.Printf("Key:Test not in\n")
 	} else {
 		fmt.Printf("Key:Test = %s\n", s)
 	}
 
+	for key, val := range MapA {
+		fmt.Printf("%-10s => %10s\n", key, val)
+	}
+
 	// delete
 	delete(MapA, "Test")
 	fmt.Println(MapA)
 
-	_, ok = MapA["Test"]
-	if !ok {
+	if _, ok := MapA["Test"]; !ok {
 		fmt.Println("Key:Test not in")
 	}
+
+	AboutSlice()
+	AboutMap()
+}
+
+func AboutSlice() {
+	var array [10]int
+	var slice []int = array[2:5]
+
+	for i := 0; i < len(array); i++ {
+		array[i] = i
+	}
+
+	for i := 0; i < len(slice); i++ {
+		fmt.Printf("Slice at %02d is %4d\n", i, slice[i])
+	}
+
+	fmt.Println("The Length of Array is", len(array))
+	fmt.Println("The Length of Slice is", len(slice))
+	fmt.Println("The Capacity of Slice is", cap(slice))
+
+	// grow the slice
+	slice = slice[:4]
+	for i, v := range slice {
+		fmt.Printf("Slice at %02d is %4d\n", i, v)
+	}
+
+	fmt.Println("The Length of Slice is", len(slice))
+	fmt.Println("The Capacity of Slice is", cap(slice))
+
+}
+
+func AboutMap() {
+	{
+		// Version A
+		items := make([]map[int]int, 5)
+		for i := range items {
+			items[i] = make(map[int]int, 1)
+			items[i][rand.Intn(100)] = rand.Intn(100)
+		}
+
+		fmt.Printf("Version A: Value of items: %v\n", items)
+	}
+
+	{
+		// Version B
+		// Invalid Method
+		items := make([]map[int]int, 5)
+		for _, item := range items {
+			item = make(map[int]int, 1)
+			item[rand.Intn(100)] = rand.Intn(100)
+		}
+
+		fmt.Printf("Version B: Value of items: %v (Invalid Method) \n", items)
+	}
 }
diff --git a/learn/go/func.go b/learn/go/func.go
index ac41afc..fe96067 100644
--- a/learn/go/func.go
+++ b/learn/go/func.go
@@ -10,8 +10,11 @@ package main
 
 import (
 	"fmt"
+	"io"
+	"log"
 	"math"
 	"math/rand"
+	"runtime"
 	"time"
 )
 
@@ -37,11 +40,33 @@ func main() {
 		fmt.Printf("Positive: %5d         Negative: %5d\n", pos(i), neg(-i*i))
 	}
 
+	where := func() {
+		_, file, line, _ := runtime.Caller(1)
+		log.Printf("%s:%d", file, line)
+	}
+
+	where()
+
 	// Fibonacci
 	fibonacci := Fibonacci()
 	for i := 0; i < 10; i++ {
 		fmt.Printf("%02d - %5d\n", i, fibonacci())
 	}
+
+	where()
+
+	// Vararg Func
+	VarArgFuncA("Google", "Apple", "Microsoft", "Tencent")
+
+	RecordRet("Golang")
+
+	where()
+
+	for i := 0; i < 10; i++ {
+		fmt.Printf("FibonacciRecursive(%d) is: %4d\n", i, FibonacciRecursive(i))
+	}
+
+	where()
 }
 
 func Adder() func(int) int {
@@ -72,3 +97,29 @@ func Fibonacci() func() int {
 
 	return innerfunc
 }
+
+// 变长参数函数
+
+// sv 的类型为[]string
+func VarArgFuncA(sv ...string) {
+	for i, s := range sv {
+		fmt.Printf("VarArgFuncA Parameter[%02d]: %s\n", i, s)
+	}
+}
+
+func RecordRet(s string) (n int, err error) {
+	defer func() {
+		log.Printf("RecordRet(%q) = %d, %v", s, n, err)
+	}()
+
+	return 7, io.EOF
+}
+
+// 递归
+func FibonacciRecursive(n int) int {
+	if n <= 1 {
+		return 1
+	}
+
+	return FibonacciRecursive(n-1) + FibonacciRecursive(n-2)
+}
diff --git a/learn/go/pattern.go b/learn/go/pattern.go
new file mode 100644
index 0000000..d1c7142
--- /dev/null
+++ b/learn/go/pattern.go
@@ -0,0 +1,58 @@
+/*
+ * ------------------------------------------------------------------------
+ *   File Name: pattern.go
+ *      Author: Zhao Yanbai
+ *              2015-11-28 20:06:28 Saturday CST
+ * Description: none
+ * ------------------------------------------------------------------------
+ */
+package main
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+)
+
+func main() {
+	defer fmt.Println("Program Exited...")
+
+	SearchStr := "John: 2578.34 William: 4567.23 Steve: 5632.18"
+	Pattern := "[0-9]+.[0-9]+"
+
+	fmt.Println(SearchStr)
+
+	if ok, _ := regexp.Match(Pattern, []byte(SearchStr)); ok {
+		fmt.Println("Match Found!")
+	}
+
+	re, _ := regexp.Compile(Pattern)
+	sa := re.ReplaceAllString(SearchStr, "##.#")
+	fmt.Println(sa)
+
+	rfunc := func(s string) string {
+		v, _ := strconv.ParseFloat(s, 32)
+
+		// FormatFloat(f float64, fmt byte, prec, bitSize int) string
+		// f:		要转换的浮点数
+		// fmt:		格式标记(b、e、E、f、g、G)
+		// prec:	精度a(数字部分的长度，不包括指数部分)
+		// bitSize:	指定浮点类型(32:float32、64:float64)
+		//
+		// 格式标记
+		// 'b' (-ddddp±ddd, 二进制指数)
+		// 'e' (-dddde±dd,  十进制指数)
+		// 'E' (-ddddE±dd,  十进制指数)
+		// 'f' (-ddd.dddd,  没有指数)
+		// 'g' ('e':大指数，'f':其它情况)
+		// 'G' ('E':大指数，'f':其它情况)
+		//
+		// 如果格式标记为 'e'，'E'和'f'，则 prec 表示小数点后的数字位数
+		// 如果格式标记为 'g'，'G'，则 prec 表示总的数字位数（整数部分+小数部分）
+
+		return "$" + strconv.FormatFloat(v*2, 'f', 2, 32)
+	}
+
+	sb := re.ReplaceAllStringFunc(SearchStr, rfunc)
+	fmt.Println(sb)
+}
diff --git a/learn/go/string.go b/learn/go/string.go
index b11352e..15798f3 100644
--- a/learn/go/string.go
+++ b/learn/go/string.go
@@ -38,6 +38,11 @@ func main() {
 	str = strings.Replace(str, "example", "示例", -1) // -1表示替换所有
 	fmt.Println(str)
 
+	var words []rune = []rune(str)
+	for i, v := range words {
+		fmt.Printf("[%02d] : %c\n", i, v)
+	}
+
 	var repeat string = "Repeat "
 	fmt.Println("Repeat:", strings.Repeat(repeat, 10))
 	fmt.Println("ToUpper:", strings.ToUpper(repeat))