Finish: 03-maps - map使用

stage03-functions/01-basic-functions/main.go

@@ -1,6 +1,9 @@
 package main
 
-import "fmt"
+import (
+	"fmt"
+	"strings"
+)
 
 func exercise1() int {
 	fmt.Println("=== 练习1：无参数单返回值函数 ===")
@@ -9,14 +12,11 @@ func exercise1() int {
 	// 定义一个函数cube，接收一个int参数，返回其立方
 	// 调用这两个函数并返回它们的和
 
-	____ func ____
+	square := func(n int) int { return n * n }
-		square := func(n int) ____ { return n * n }
-		____
-	}
 
-	cube := func(n int) ____ { ____ }
+	cube := func(n int) int { return n * n * n }
 
-	return ____(3) + ____(2)
+	return square(3) + cube(2)
 }
 
 func exercise2(a, b int) {
@@ -25,19 +25,23 @@ func exercise2(a, b int) {
 	// 定义一个函数，接收两个int参数a和b
 	// 打印a + b, a - b, a * b
 	// 格式: "加: 5, 减: 1, 乘: 6"
-	fmt.Printf("加: %d, 减: %d, 乘: %d\n", ____, ____, ____)
+	sum := a + b
+	difference := a - b
+	product := a * b
+
+	fmt.Printf("加: %d, 减: %d, 乘: %d\n", sum, difference, product)
 }
 
 func exercise3(nums ...int) int {
 	fmt.Println("\n=== 练习3：可变参数 ===")
 
 	// 定义一个可变参数函数，计算所有数字的和
-	sum := ____
+	sum := 0
-	for _, num := range ____ {
+	for _, num := range nums {
-		____
+		sum += num
 	}
 
-	return ____
+	return sum
 }
 
 func exercise4(name, city string) (string, string) {
@@ -47,13 +51,13 @@ func exercise4(name, city string) (string, string) {
 	// nameWithGreeting: 格式为 "Hello, {name}"
 	// info: 格式为 "{name} lives in {city}"
 
-	var ____ string
+	var nameWithGreeting string
-	var ____
+	var info string
 
 	nameWithGreeting = fmt.Sprintf("Hello, %s", name)
 	info = fmt.Sprintf("%s lives in %s", name, city)
 
-	return ____, ____
+	return nameWithGreeting, info
 }
 
 func exercise5(name string) string {
@@ -63,13 +67,13 @@ func exercise5(name string) string {
 	// 返回大写的name
 	// 提示：使用strings.ToUpper
 
-	____ := ____
+	upperName := strings.ToUpper(name)
 
-	return ____
+	return upperName
 }
 
 func main() {
-	fmt.Println("=== 基础函数 练习 ===\n")
+	fmt.Println("=== 基础函数 练习 ===")
 
 	result1 := exercise1()
 	fmt.Printf("练习1结果: %d\n", result1)

stage03-functions/02-multiple-returns/main.go

@@ -1,42 +1,40 @@
 package main
 
 import (
-	"errors"
 	"fmt"
-	"time"
 )
 
 func exercise1(x, y int) (int, int) {
 	// 返回x+y和x-y
-	return ____, ____
+	return x + y, x - y
 }
 
 func exercise2(n int) (int, error) {
 	// 如果n<0，返回0和错误
 	// 否则返回n和nil
-	if ____ {
+	if n < 0 {
-		return ____, ____
+		return n, fmt.Errorf("division by zero")
 	}
-	return ____, ____
+	return n, nil
 }
 
 func exercise3(s string) (bool, int) {
 	// 返回字符串是否包含"hello"和字符串长度
 	contains := true
-	length := ____
+	length := len(s)
-	return ____, ____
+	return contains, length
 }
 
 func main() {
-	fmt.Println("=== 多返回值 练习 ===\n")
+	fmt.Println("=== 多返回值 练习 ===")
 
 	sum, diff := exercise1(10, 3)
-	fmt.Printf("练习1: 加=%d, 减=%d\n", ____, ____)
+	fmt.Printf("练习1: 加=%d, 减=%d\n", sum, diff)
 
 	result, err := exercise2(-5)
-	if ____ {
+	if err != nil {
-		fmt.Printf("练习2: 错误 = %v\n", ____)
+		fmt.Printf("练习2: 错误 = %v\n", result)
 	} else {
-		fmt.Printf("练习2: 结果 = %d\n", ____)
+		fmt.Printf("练习2: 结果 = %d\n", result)
 	}
 }

stage03-functions/03-closures/main.go

@@ -9,11 +9,11 @@ func exercise1() func(int) int {
 	// 该闭包接收一个int参数并返回乘以multiplier的结果
 
 	multiplier := 3
-	____ := func(num int) ____ {
+	multifunc := func(num int) int {
-		return ____
+		return multiplier * num
 	}
 
-	return ____
+	return multifunc
 }
 
 func exercise2() func() int {
@@ -23,14 +23,14 @@ func exercise2() func() int {
 	// 每次调用返回的函数时，计数器加1
 	// 提示：使用匿名函数捕获外部变量
 
-	count := ____
+	count := 0
 
-	____ := func() ____ {
+	countfunc := func() int {
-		____
+		count++
-		return ____
+		return count
 	}
 
-	return ____
+	return countfunc
 }
 
 func exercise3() func() int {
@@ -40,15 +40,15 @@ func exercise3() func() int {
 	// 每次调用返回下一个斐波那契数
 	// 数列: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34...
 
-	a, b := ____, ____
+	a, b := 0, 1
 
-	____ := func() ____ {
+	fib := func() int {
-		result := ____
+		result := a
-		a, b = ____
+		a, b = b, a+b
-		return ____
+		return result
 	}
 
-	return ____
+	return fib
 }
 
 func exercise4() func(int) bool {
@@ -59,13 +59,13 @@ func exercise4() func(int) bool {
 	// 检查函数判断输入数字是否在[min, max]范围内
 
 	min := 10
-	max := ____
+	max := 20
 
-	____ := func(num int) ____ {
+	check := func(num int) bool {
-		return num >= ____ && num <= ____
+		return num >= min && num <= max
 	}
 
-	return ____
+	return check
 }
 
 func exercise5(start int) func(int) int {
@@ -75,18 +75,18 @@ func exercise5(start int) func(int) int {
 	// 从start开始，每次调用累加参数值
 	// 提示：闭包应该能访问外部作用域的变量
 
-	total := ____
+	total := start
 
-	____ := func(n int) ____ {
+	adder := func(n int) int {
-		____
+		total += n
-		return ____
+		return total
 	}
 
-	return ____
+	return adder
 }
 
 func main() {
-	fmt.Println("=== 闭包 练习 ===\n")
+	fmt.Println("=== 闭包 练习 ===")
 
 	add3 := exercise1()
 	fmt.Printf("练习1结果: add3(4) = %d\n", add3(4))

stage03-functions/04-higher-order/main.go

@@ -8,9 +8,9 @@ func exercise1(apply func(int) int, value int) int {
 	// 接收一个函数apply和一个值value
 	// 调用apply函数处理value并返回结果
 
-	result := ____
+	result := apply(value)
 
-	return ____
+	return result
 }
 
 func exercise2() func(int) int {
@@ -19,7 +19,9 @@ func exercise2() func(int) int {
 	// 返回一个函数，该函数将输入值乘以2
 	// 提示：返回一个匿名函数
 
-	return ____
+	return func(x int) int {
+		return x * 2
+	}
 }
 
 func exercise3(vals []int, filter func(int) bool) []int {
@@ -28,15 +30,15 @@ func exercise3(vals []int, filter func(int) bool) []int {
 	// 接收一个int切片和一个过滤函数
 	// 返回过滤后的切片（只保留满足条件的元素）
 
-	var result ____
+	var result []int
 
-	for _, val := range ____ {
+	for _, val := range vals {
-		if ____(val) {
+		if filter(val) {
-			result = append(result, ____)
+			result = append(result, val)
 		}
 	}
 
-	return ____
+	return result
 }
 
 func exercise4(vals []int, mapper func(int) int) []int {
@@ -45,13 +47,13 @@ func exercise4(vals []int, mapper func(int) int) []int {
 	// 接收一个int切片和一个映射函数
 	// 返回映射后的切片（每个元素都经过mapper函数处理）
 
-	result := make([]int, ____)
+	result := make([]int, len(vals))
 
-	for i, val := range ____ {
+	for i, val := range vals {
-		result[i] = ____(val)
+		result[i] = mapper(val)
 	}
 
-	return ____
+	return result
 }
 
 func exercise5(vals []int, reducer func(int, int) int, initial int) int {
@@ -61,13 +63,13 @@ func exercise5(vals []int, reducer func(int, int) int, initial int) int {
 	// 返回归约结果
 	// 例如：对切片求和、求积等
 
-	result := ____
+	result := initial
 
-	for _, val := range ____ {
+	for _, val := range vals {
-		result = ____(result, val)
+		result = reducer(result, val)
 	}
 
-	return ____
+	return result
 }
 
 func exercise6() int {
@@ -79,18 +81,18 @@ func exercise6() int {
 	// 返回 double(square(3)) 的结果
 	// 即：先平方(9)，再双倍(18)
 
-	square := func(n int) int { return ____ }
+	square := func(n int) int { return n * n }
-	double := func(n int) int { return ____ }
+	double := func(n int) int { return n * 2 }
 
 	compose := func(f, g func(int) int, x int) int {
-		return ____(____(x))
+		return g(f(x))
 	}
 
-	return compose(____, ____, 3)
+	return compose(square, double, 3)
 }
 
 func main() {
-	fmt.Println("=== 高阶函数 练习 ===\n")
+	fmt.Println("=== 高阶函数 练习 ===")
 
 	平方 := func(n int) int { return n * n }
 	result1 := exercise1(平方, 4)

stage04-composite-types/01-arrays/main.go

@@ -7,13 +7,13 @@ func exercise1() [5]int {
 
 	// 声明一个长度为5的int数组
 	// 初始化所有元素为10
-	var arr ____
+	var arr [5]int
 
-	for i := 0; i < ____(arr); i++ {
+	for i := 0; i < len(arr); i++ {
-		arr[i] = ____
+		arr[i] = 10
 	}
 
-	return ____
+	return arr
 }
 
 func exercise2() string {
@@ -22,7 +22,7 @@ func exercise2() string {
 	// 修改数组元素并返回修改后的字符串表示
 	fruits := [4]string{"苹果", "香蕉", "橙子", "葡萄"}
 
-	fruits[____] = "芒果"
+	fruits[0] = "芒果"
 
 	fmt.Printf("修改后的水果: %s\n", fruits)
 
@@ -35,13 +35,13 @@ func exercise3() int {
 	// 计算数组所有元素的和
 	numbers := [5]int{10, 20, 30, 40, 50}
 
-	sum := ____
+	sum := 0
 
-	for i := 0; i < ____(numbers); i++ {
+	for i := 0; i < len(numbers); i++ {
-		sum += ____
+		sum += numbers[i]
 	}
 
-	return ____
+	return sum
 }
 
 func exercise4() [3]int {
@@ -51,11 +51,11 @@ func exercise4() [3]int {
 	// 修改原数组，观察拷贝的数组是否变化
 	arr1 := [3]int{1, 2, 3}
 
-	arr2 := ____
+	arr2 := arr1
 
 	arr1[0] = 99
 
-	return ____
+	return arr2
 }
 
 func exercise5() int {
@@ -64,19 +64,19 @@ func exercise5() int {
 	// 计算二维数组的和
 	matrix := [3][2]int{{1, 2}, {3, 4}, {5, 6}}
 
-	sum := ____
+	sum := 0
 
-	for i := 0; i < ____(matrix); i++ {
+	for i := 0; i < len(matrix); i++ {
-		for j := 0; j < ____(matrix[i]); j++ {
+		for j := 0; j < len(matrix[i]); j++ {
-			sum += ____
+			sum += matrix[i][j]
 		}
 	}
 
-	return ____
+	return sum
 }
 
 func main() {
-	fmt.Println("=== 数组 练习 ===\n")
+	fmt.Println("=== 数组 练习 ===")
 
 	result1 := exercise1()
 	fmt.Printf("练习1结果: %v\n", result1)

stage04-composite-types/02-slices/main.go

@@ -6,10 +6,10 @@ func exercise1() []int {
 	fmt.Println("=== 练习1：切片声明与初始化 ===")
 
 	// 创建一个长度为3的int切片，初始值为[1, 2, 3]
-	s := make([]int, ____)
+	s := make([]int, 3)
-	s[0], s[1], s[2] = ____, ____, ____
+	s[0], s[1], s[2] = 1, 2, 3
 
-	return ____
+	return s
 }
 
 func exercise2() int {
@@ -17,10 +17,10 @@ func exercise2() int {
 
 	// 向切片中添加元素并返回新长度
 	fruits := []string{"苹果", "香蕉"}
-	fruits = append(fruits, ____)
+	fruits = append(fruits, "梨子")
-	fruits = append(fruits, ____, ____)
+	fruits = append(fruits, "蓝莓", "草莓")
 
-	return ____(fruits)
+	return len(fruits)
 }
 
 func exercise3() []int {
@@ -29,14 +29,14 @@ func exercise3() []int {
 	// 从切片中提取子切片
 	numbers := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
 
-	// 提取索引2到6（不包含6）
+	// 提取索引2到5（不包含5）
-	sub1 := numbers[____:____]
+	sub1 := numbers[2:5]
 
 	// 提取前5个元素
-	sub2 := numbers[:____]
+	sub2 := numbers[:5]
 
 	// 提取从第5个开始到末尾
-	sub3 := numbers[____:]
+	sub3 := numbers[4:]
 
 	fmt.Printf("子切片1: %v\n", sub1)
 	fmt.Printf("子切片2: %v\n", sub2)
@@ -50,13 +50,13 @@ func exercise4() int {
 
 	// 修改原始切片，观察使用copy复制的切片是否受影响
 	s1 := []int{1, 2, 3}
-	s2 := make([]int, ____(s1))
+	s2 := make([]int, len(s1))
 
-	copy(____, s1)
+	copy(s2, s1)
 
 	s1[0] = 99
 
-	return ____
+	return s2[0]
 }
 
 func exercise5() []int {
@@ -65,19 +65,19 @@ func exercise5() []int {
 	// 创建一个新切片，包含原切片中所有偶数
 	numbers := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
 
-	var evens ____
+	var evens []int
 
-	for _, num := range ____ {
+	for _, num := range numbers {
-		if num%2 == ____ {
+		if num%2 == 0 {
-			evens = append(____, num)
+			evens = append(evens, num)
 		}
 	}
 
-	return ____
+	return evens
 }
 
 func main() {
-	fmt.Println("=== 切片 练习 ===\n")
+	fmt.Println("=== 切片 练习 ===")
 
 	result1 := exercise1()
 	fmt.Printf("练习1结果: %v\n", result1)

stage04-composite-types/03-maps/main.go

@@ -7,13 +7,13 @@ func exercise1() map[string]int {
 
 	// 创建一个map，键为string类型，值为int类型
 	// 添加"张三": 90, "李四": 85, "王五": 95
-	scores := ____
+	scores := make(map[string]int)
 
-	scores["张三"] = ____
+	scores["张三"] = 90
-	scores["李四"] = ____
+	scores["李四"] = 85
-	scores["王五"] = ____
+	scores["王五"] = 95
 
-	return ____
+	return scores
 }
 
 func exercise2() string {
@@ -25,7 +25,7 @@ func exercise2() string {
 		"李四": 85,
 	}
 
-	score, exists := ____
+	score, exists := scores["李四"]
 
 	if exists {
 		fmt.Printf("李四的分数是: %d\n", score)
@@ -45,13 +45,13 @@ func exercise3() int {
 		"赵六": 88,
 	}
 
-	sum := ____
+	sum := 0
 
-	for ____, score := range ____ {
+	for _, score := range scores {
-		sum += ____
+		sum += score
 	}
 
-	return ____
+	return sum
 }
 
 func exercise4() map[string]int {
@@ -64,9 +64,9 @@ func exercise4() map[string]int {
 		"王五": 95,
 	}
 
-	____(scores, "李四")
+	delete(scores, "李四")
 
-	return ____
+	return scores
 }
 
 func exercise5() []string {
@@ -81,19 +81,19 @@ func exercise5() []string {
 		"钱七": 92,
 	}
 
-	var topStudents ____
+	var topStudents []string
 
-	for name, score := range ____ {
+	for name, score := range scores {
-		if score >= ____ {
+		if score >= 90 {
-			topStudents = append(____, ____)
+			topStudents = append(topStudents, name)
 		}
 	}
 
-	return ____
+	return topStudents
 }
 
 func main() {
-	fmt.Println("=== map 练习 ===\n")
+	fmt.Println("=== map 练习 ===")
 
 	result1 := exercise1()
 	fmt.Printf("练习1结果: %v\n", result1)