array sorting

array sorting

Examples of how to sort an array

Node.js

const stringArray = ['a', 'd', 'z', 'b', 'c', 'y']
const stringArraySortedAsc = stringArray.sort((a, b) => a > b ? 1 : -1)
console.log(stringArraySortedAsc)

const stringArraySortedDesc = stringArray.sort((a, b) => a > b ? -1 : 1)
console.log(stringArraySortedDesc)

const numberArray = [1, 3, 5, 9, 4, 2, 0]
const numberArraySortedAsc = numberArray.sort((a, b) => a - b)
console.log(numberArraySortedAsc)

const numberArraySortedDesc = numberArray.sort((a, b) => b - a)
console.log(numberArraySortedDesc)

const collection = [
    {
        name: "Li L",
        age: 8
    },
    {
        name: "Json C",
        age: 3
    },
    {
        name: "Zack W",
        age: 15
    },
    {
        name: "Yi M",
        age: 2
    }
]

const collectionSortedByAgeAsc = collection.sort((a, b) => a.age - b.age)
console.log(collectionSortedByAgeAsc)

const collectionSortedByAgeDesc = collection.sort((a, b) => b.age - a.age)
console.log(collectionSortedByAgeDesc)

Output

[ 'a', 'b', 'c', 'd', 'y', 'z' ]
[ 'z', 'y', 'd', 'c', 'b', 'a' ]
[ 0, 1, 2, 3, 4, 5, 9 ]
[ 9, 5, 4, 3, 2, 1, 0 ]
[ { name: 'Yi M', age: 2 },
  { name: 'Json C', age: 3 },
  { name: 'Li L', age: 8 },
  { name: 'Zack W', age: 15 } ]
[ { name: 'Zack W', age: 15 },
  { name: 'Li L', age: 8 },
  { name: 'Json C', age: 3 },
  { name: 'Yi M', age: 2 } ]

Go

package main

import (
    "fmt"
    "sort"
)

type Person struct {
    Name string
    Age  int
}

type PersonCollection []Person

func (pc PersonCollection) Len() int {
    return len(pc)
}

func (pc PersonCollection) Swap(i, j int) {
    pc[i], pc[j] = pc[j], pc[i]
}

func (pc PersonCollection) Less(i, j int) bool {
    // asc
    return pc[i].Age < pc[j].Age
}

func main() {
    intList := []int{1, 3, 5, 9, 4, 2, 0}

    // asc
    sort.Ints(intList)
    fmt.Println(intList)
    // desc
    sort.Sort(sort.Reverse(sort.IntSlice(intList)))
    fmt.Println(intList)

    stringList := []string{"a", "d", "z", "b", "c", "y"}

    // asc
    sort.Strings(stringList)
    fmt.Println(stringList)
    // desc
    sort.Sort(sort.Reverse(sort.StringSlice(stringList)))
    fmt.Println(stringList)

    collection := []Person{
        {"Li L", 8},
        {"Json C", 3},
        {"Zack W", 15},
        {"Yi M", 2},
    }

    // asc
    sort.Sort(PersonCollection(collection))
    fmt.Println(collection)
    // desc
    sort.Sort(sort.Reverse(PersonCollection(collection)))
    fmt.Println(collection)
}

Output

[0 1 2 3 4 5 9]
[9 5 4 3 2 1 0]
[a b c d y z]
[z y d c b a]
[{Yi M 2} {Json C 3} {Li L 8} {Zack W 15}]
[{Zack W 15} {Li L 8} {Json C 3} {Yi M 2}]