package main

import (
    "fmt"
    "strconv"
)

// map reduce filter and pippline

func itemsFilter(items []map[string]string, f func(map[string]string) bool) []map[string]string {
    newSlice := make([]map[string]string, 0)
    for _, item := range items {
        if f(item) {
            newSlice = append(newSlice, item)
        }
    }
    fmt.Println("itemsFilter result: ", newSlice)
    return newSlice
}

func mapToString(items []map[string]string, f func(map[string]string) string) []string {
    newSlice := make([]string, 0)
    for _, item := range items {
        newSlice = append(newSlice, f(item))
    }
    fmt.Println("mapToString resutl: ", newSlice)
    return newSlice
}

func fieldSum(items []string, f func(string) int) int {
    var sum int
    for _, item := range items {
        sum += f(item)
    }
    return sum
}

func main() {
    var users = []map[string]string{
        {
            "name": "张三",
            "age":  "18",
        },
        {
            "name": "李四",
            "age":  "22",
        },
        {
            "name": "王五",
            "age":  "20",
        },
        {
            "name": "赵六",
            "age":  "-10",
        },
        {
            "name": "孙七",
            "age":  "60",
        },
        {
            "name": "周八",
            "age":  "10",
        },
    }
    validUsers := itemsFilter(users, func(user map[string]string) bool {
        age, ok := user["age"]
        if !ok {
            return false
        }
        intAge, err := strconv.Atoi(age)
        if err != nil {
            return false
        }
        if intAge < 18 || intAge > 35 {
            return false
        }
        return true
    })

    ageSlice := mapToString(validUsers, func(user map[string]string) string {
        return user["age"]
    })

    sum := fieldSum(ageSlice, func(age string) int {
        intAge, _ := strconv.Atoi(age)
        return intAge
    })
    fmt.Printf("用户年龄累加结果: %d\n", sum)
}

package main

import (
    "fmt"
    "strconv"
)

// map reduce filter and pippline

func itemsFilter(items []map[string]string, f func(map[string]string) bool) []map[string]string {
    newSlice := make([]map[string]string, 0)
    for _, item := range items {
        if f(item) {
            newSlice = append(newSlice, item)
        }
    }
    fmt.Println("itemsFilter result: ", newSlice)
    return newSlice
}

func mapToString(items []map[string]string, f func(map[string]string) string) []string {
    newSlice := make([]string, 0)
    for _, item := range items {
        newSlice = append(newSlice, f(item))
    }
    fmt.Println("mapToString resutl: ", newSlice)
    return newSlice
}

func fieldSum(items []string, f func(string) int) int {
    var sum int
    for _, item := range items {
        sum += f(item)
    }
    return sum
}

func main() {
    var users = []map[string]string{
        {
            "name": "张三",
            "age":  "18",
        },
        {
            "name": "李四",
            "age":  "22",
        },
        {
            "name": "王五",
            "age":  "20",
        },
        {
            "name": "赵六",
            "age":  "-10",
        },
        {
            "name": "孙七",
            "age":  "60",
        },
        {
            "name": "周八",
            "age":  "10",
        },
    }
    validUsers := itemsFilter(users, func(user map[string]string) bool {
        age, ok := user["age"]
        if !ok {
            return false
        }
        intAge, err := strconv.Atoi(age)
        if err != nil {
            return false
        }
        if intAge < 18 || intAge > 35 {
            return false
        }
        return true
    })

    ageSlice := mapToString(validUsers, func(user map[string]string) string {
        return user["age"]
    })

    sum := fieldSum(ageSlice, func(age string) int {
        intAge, _ := strconv.Atoi(age)
        return intAge
    })
    fmt.Printf("用户年龄累加结果: %d\n", sum)
}