Feel free to flag this question if this is a duplicate and feel free to reword the title if you have better title. I did not know how to word the title. I have 2 different arrays. First array contains a set of users and second array contains a set of avatars. It's important to mention that the array of avatars will always be bigger than users. I need to pair only one avatar per user. Each user should not have the same avatar and each avatar should match the user's gender. How can I achieve this?

avatars = [
    {
        "id" : 1,
        "image" : "maleavatar1",
        "gender": "male"
    },
    {
        "id" : 2,
        "image" : "maleavatar2",
        "gender": "male"
    },
    {
        "id" : 3,
        "image" : "maleavatar3",
        "gender": "male"
    },
    {
        "id" : 4,
        "image" : "femaleavatar1",
        "gender": "female"
    },
    {
        "id" : 5,
        "image" : "femaleavatar2",
        "gender": "female"
    },
    {
        "id" : 6,
        "image" : "femaleavatar3",
        "gender": "female"
    },
    {
        "id" : 7,
        "image" : "femaleavatar4",
        "gender": "female"
    },

]
users = [
    {
        "id" : 1,
        "name" : "Manila",
        "gender": "female"
    },
    {
        "id" : 2,
        "name" : "Josy",
        "gender": "female"
    },
    {
        "id" : 3,
        "name" : "Eliza",
        "gender": "female"
    },
    {
        "id" : 4,
        "name" : "Martin",
        "gender": "male"
    },
    {
        "id" : 5,
        "name" : "Mark",
        "gender": "male"
    },
    {
        "id" : 6,
        "name" : "John",
        "gender": "male"
    }

]

var count = 0;
var randUser = '';
var randos = [];
var b_s = users.length;
var a_s = avatars.length;

users.forEach(function(user){count  
    
avatars.forEach(function(avatar){

if(avatar.gender === user.gender){

randUser = {

    "name" : user.name,
    "avatar" : avatar.image,
    "gender" : user.gender


}

  //push users
randos.push(randUser);

}

})

})
console.log(randos);

CodePudding user response：

It's a good practice, when you hear "random without duplicates", to think "shuffle".

So to assign random, non-repeating, correctly gendered avatars, segregate the avatars by gender, shuffle the male and female avatars, then assign them sequentially to users....

const avatars = getAvatars();  // just to move the data to the bottom of the snippet
const users = getUsers();

const shuffledMales = shuffle(avatars.filter(a => a.gender==="male"));
const shuffledFemales = shuffle(avatars.filter(a => a.gender==="female"));

let maleIndex = 0, femaleIndex = 0;
users.forEach(user => {
  user.avatar = user.gender === "male" ? shuffledMales[maleIndex  ] : shuffledFemales[femaleIndex  ];
});

console.log(users);

// fisher-yates shuffle, adapted from https://bost.ocks.org/mike/shuffle/
function shuffle(array) {
  let copy = [],
    n = array.length,
    i;
  while (n) {
    let i = Math.floor(Math.random() * array.length);
    if (i in array) {
      copy.push(array[i]);
      delete array[i];
      n--;
    }
  }
  return copy;
}

function getAvatars() {
  return [{
      "id": 1,
      "image": "maleavatar1",
      "gender": "male"
    },
    {
      "id": 2,
      "image": "maleavatar2",
      "gender": "male"
    },
    {
      "id": 3,
      "image": "maleavatar3",
      "gender": "male"
    },
    {
      "id": 4,
      "image": "femaleavatar1",
      "gender": "female"
    },
    {
      "id": 5,
      "image": "femaleavatar2",
      "gender": "female"
    },
    {
      "id": 6,
      "image": "femaleavatar3",
      "gender": "female"
    },
    {
      "id": 7,
      "image": "femaleavatar4",
      "gender": "female"
    },
  ];
}

function getUsers() {
  return [{
      "id": 1,
      "name": "Manila",
      "gender": "female"
    },
    {
      "id": 2,
      "name": "Josy",
      "gender": "female"
    },
    {
      "id": 3,
      "name": "Eliza",
      "gender": "female"
    },
    {
      "id": 4,
      "name": "Martin",
      "gender": "male"
    },
    {
      "id": 5,
      "name": "Mark",
      "gender": "male"
    },
    {
      "id": 6,
      "name": "John",
      "gender": "male"
    }
  ];
}

CodePudding user response：

You can simply do a for for the players and generate a random number between 0 and the maximum number of avatars, then check the gender and if it coincides with that of the player then assign it, once this is done add the avatar id in a another array and before assigning the next avatar check that the id of the avatars in not in the array just created

Or you can do a simply merge of the 2 array