Go基础编程实践（四）—— 数组和map

数组去重

package main

import "fmt"

func main(){
  intslice := []int{1,5,5,5,5,7,8,6,6, 6}
  fmt.println(intslice)
  uniqueintslice := unique(intslice)
  fmt.println(uniqueintslice)
}

func unique(intslice []int) []int{
  keys := make(map[int]bool)
  uniqueelements := []int{}
  for _,entry := range intslice {
    if _, value := keys[entry]; !value{
      keys[entry] =true
      uniqueelements = append(uniqueelements, entry)
    }
  }
  return uniqueelements
}

查找元素

package main

import (
  "fmt"
  "sort"
)

func main() {
  str := []string{"sandy", "provo", "st.george", "salt lake city", "draper", "south jordan", "murray"}

  // for循环查找
  for i, v := range str {
    if v == "sandy" {
      fmt.println(i)
    }
  }

  // sort包排序后查找
  // stringslice给[]string添加方法以满足interface接口，以便排序为递增序列。
  sortedlist := sort.stringslice(str)
  // 升序
  sortedlist.sort()
  fmt.println(sortedlist)
  index := sortedlist.search("sandy")
  fmt.println(index)
}

数组降序

package main

import (
  "sort"
  "fmt"
)

func main() {
  numbers := []int{1, 5, 3, 6, 2, 10, 8}
  // intslice给[]int添加方法以满足interface接口，以便排序为递增序列。
  tobesorted := sort.intslice(numbers)
  // reverse包装一个interface接口并返回一个新的interface接口，对该接口排序可生成递减序列。
  sort.sort(sort.reverse(tobesorted))
  fmt.println(tobesorted)
}

迭代数组

package main

import "fmt"

func main(){
  numbers := []int{1, 5, 3, 6, 2, 10, 8}

  for index,value := range numbers{
     fmt.printf("index: %v and value: %v\n", index, value)
  }
}

将map转为数组

package main

import "fmt"

type nameage struct{
  name string
  age int
}

func main(){
  var nameageslice []nameage
  nameages := map[string]int{
    "michael": 30,
    "john": 25,
    "jessica": 26,
    "ali": 18,
  }
  for key, value := range nameages{
    nameageslice = append(nameageslice, nameage {key, value})
  }

  fmt.println(nameageslice)

}

合并数组

package main

import "fmt"

func main(){
  items1 := []int{3,4}
  items2 := []int{1,2}
  result := append(items1, items2...)
  fmt.println(result)
}

合并map

package main

import "fmt"

func main(){
  map1 := map[string]int {
   "michael":10,
   "jessica":20,
   "tarik":33,
   "jon": 22,
  }
  fmt.println(map1)

  map2 := map[string]int {
    "lord":11,
    "of":22,
    "the":36,
    "rings": 23,
  }
  for key, value := range map2{
    map1[key] = value
  }
  fmt.println(map1)
}

判断map中key是否存在

package main

import "fmt"

func main() {
  nameages := map[string]int{
    "tarik": 32,
    "michael": 30,
    "jon": 25,
    "jessica" : 20,
  }
  if _, exists := nameages["jessica"]; exists{
    fmt.println("jessica can be found")
  }else {
    fmt.println("jessica cannot be found")
  }
}