Formatting Arrays of Objects

Question

Formatting Arrays of Objects

Looking to reformat an object in this structure:

 var data =  {
      "student": [
        [
          "name",
          "age"
        ],
        [
          "Tom",
          12
        ],
        [
          "Jack",
          13
        ]
      ]
    };

The desired output should be:

 var result =  {
      "student": [
        {
          "name": "Tom",
          "age": 12
        },
        {
          "name": "Jack",
          "age": 13
        }
      ]
    }

An attempt was made using the following code:

var response = [];  
var keysCount = req.result[0].length; 
var responseCount = req.result.length - 1; 
var i = 0,
    j = 0,
    key;

for (j = 0; j < responseCount; j++) {
    for (i = 0; i < keysCount; i++) {
        key = req.result[0][i];
        response[j][key] = req.result[j + 1][i];
    }
} 
return response;

Unfortunately, the outcome did not meet the expected results.

javascript arrays object

Answer 1

Answer №1

One way to handle this situation is by iterating through the initial array and generating an array of objects for all subsequent arrays. Matching indexes are used to assign properties to the object:

var data = {
  "student": [
    [
      "name",
      "age"
    ],
    [
      "Tom",
      12
    ],
    [
      "Jack",
      13
    ]
  ]
};
// Extract the header array
var headers = data.student[0];
// Generate a new array by mapping over the other entries...
var newArray = data.student.slice(1).map(function(entry) {
  // Create a new object
  var newObj = {};
  
  // Populate it with values from matching indexes
  headers.forEach(function(key, index) {
    newObj[key] = entry[index];
  });
  
  // Return the new object
  return newObj;
});
console.log(newArray);

Answer 2

One way to handle this situation is by iterating through the initial array and generating an array of objects for all subsequent arrays. Matching indexes are used to assign properties to the object:

var data = {
  "student": [
    [
      "name",
      "age"
    ],
    [
      "Tom",
      12
    ],
    [
      "Jack",
      13
    ]
  ]
};
// Extract the header array
var headers = data.student[0];
// Generate a new array by mapping over the other entries...
var newArray = data.student.slice(1).map(function(entry) {
  // Create a new object
  var newObj = {};
  
  // Populate it with values from matching indexes
  headers.forEach(function(key, index) {
    newObj[key] = entry[index];
  });
  
  // Return the new object
  return newObj;
});
console.log(newArray);

Answer 3

Answer №2

One approach is to create a function called tabularize that can organize an array of data with headers and rows.

This code snippet utilizes ES6. For ES5 compatibility, consider using a transpiler like Babel.

// original data structure   
var request = {
  "student": [
    [
      "name",
      "age"
    ],
    [
      "Tom",
      12
    ],
    [
      "Jack",
      13
    ]
  ]
};

// define tabularize function
var tabularize = ([headers, ...rows])=>
  rows.map(row=>
    headers.reduce((acc,h,i)=>
      Object.assign(acc, {[h]: row[i]}), {}));

// transform the object 
var request2 = {student: tabularize(request.student)};

// output the result
console.log(request2);

//=> {"student":[{"name":"Tom","age":12},{"name":"Jack","age":13}]}

You can also structure the request object directly by utilizing the tabularize function during object creation

// tabularize function
var tabularize = ([headers, ...rows])=>
  rows.map(row=>
    headers.reduce((acc,h,i)=>
      Object.assign(acc, {[h]: row[i]}), {}));

// specify the request object
var request = {
  student: tabularize([
    [
      "name",
      "age"
    ],
    [
      "Tom",
      12
    ],
    [
      "Jack",
      13
    ]
  ])
};

// display the outcome
console.log(request);

//=> {"student":[{"name":"Tom","age":12},{"name":"Jack","age":13}]}

Answer 4

One approach is to create a function called tabularize that can organize an array of data with headers and rows.

This code snippet utilizes ES6. For ES5 compatibility, consider using a transpiler like Babel.

// original data structure   
var request = {
  "student": [
    [
      "name",
      "age"
    ],
    [
      "Tom",
      12
    ],
    [
      "Jack",
      13
    ]
  ]
};

// define tabularize function
var tabularize = ([headers, ...rows])=>
  rows.map(row=>
    headers.reduce((acc,h,i)=>
      Object.assign(acc, {[h]: row[i]}), {}));

// transform the object 
var request2 = {student: tabularize(request.student)};

// output the result
console.log(request2);

//=> {"student":[{"name":"Tom","age":12},{"name":"Jack","age":13}]}

You can also structure the request object directly by utilizing the tabularize function during object creation

// tabularize function
var tabularize = ([headers, ...rows])=>
  rows.map(row=>
    headers.reduce((acc,h,i)=>
      Object.assign(acc, {[h]: row[i]}), {}));

// specify the request object
var request = {
  student: tabularize([
    [
      "name",
      "age"
    ],
    [
      "Tom",
      12
    ],
    [
      "Jack",
      13
    ]
  ])
};

// display the outcome
console.log(request);

//=> {"student":[{"name":"Tom","age":12},{"name":"Jack","age":13}]}

Answer 5

Answer №3

To begin, let's create a simple function that constructs an object from two arrays - one containing keys and the other their corresponding values:

function makeObjectFromPairs(keys, values) {
  var object = {};

  for (var i = 0; i < keys.length; i++) {
    object[keys[i]] = values[i];
  }

  return object;
}

// makeObjectFromPairs(['a', 'b'], [1, 2]) === {a: 1, b: 2}

Next, we can utilize the first element of the students array as the keys, and each subsequent element as the values.

var keys = students[0];
var result = [];

for (var i = 1; i < students.length; i++) {
  result.push(makeObjectFromPairs(keys, students[i]);
}

While you may opt to use Array#map or similar methods instead of loops, this straightforward approach is often easier to grasp.

Correcting your initial code snippet

Given your earnest attempt at solving the task independently, let's take a closer look at your code to pinpoint the error. The crucial fix involves initializing each element in your output as an empty object before populating it with key/value pairs.

for (j = 0; j < responseCount; j++) {

    // Remember to set the response element to an empty object here.
    response[j] = {};

Answer 6

To begin, let's create a simple function that constructs an object from two arrays - one containing keys and the other their corresponding values:

function makeObjectFromPairs(keys, values) {
  var object = {};

  for (var i = 0; i < keys.length; i++) {
    object[keys[i]] = values[i];
  }

  return object;
}

// makeObjectFromPairs(['a', 'b'], [1, 2]) === {a: 1, b: 2}

Next, we can utilize the first element of the students array as the keys, and each subsequent element as the values.

var keys = students[0];
var result = [];

for (var i = 1; i < students.length; i++) {
  result.push(makeObjectFromPairs(keys, students[i]);
}

While you may opt to use Array#map or similar methods instead of loops, this straightforward approach is often easier to grasp.

Correcting your initial code snippet

Given your earnest attempt at solving the task independently, let's take a closer look at your code to pinpoint the error. The crucial fix involves initializing each element in your output as an empty object before populating it with key/value pairs.

for (j = 0; j < responseCount; j++) {

    // Remember to set the response element to an empty object here.
    response[j] = {};

Answer 7

Answer №4

This is an alternative solution:

var data = {
    "people": [
        [
            "name",
            "age"
        ],
        [
            "Sally",
            22
        ],
        [
            "Mike",
            30
        ]
    ]
};

var result = {};
var peopleList = [];
var count = data.people.length - 1;
var i = 0,
    key;

for (i = 0; i < count; i++) {
    var person = {};
    data.people[0].forEach(function(attribute, index) {
        person[attribute] = data.people[1 + i][index];
    });
    peopleList.push(person)
}

result["people"] = peopleList;

console.log(result); // {"people":[{"name":"Sally","age":22},{"name":"Mike","age":30}]}

Answer 8

This is an alternative solution:

var data = {
    "people": [
        [
            "name",
            "age"
        ],
        [
            "Sally",
            22
        ],
        [
            "Mike",
            30
        ]
    ]
};

var result = {};
var peopleList = [];
var count = data.people.length - 1;
var i = 0,
    key;

for (i = 0; i < count; i++) {
    var person = {};
    data.people[0].forEach(function(attribute, index) {
        person[attribute] = data.people[1 + i][index];
    });
    peopleList.push(person)
}

result["people"] = peopleList;

console.log(result); // {"people":[{"name":"Sally","age":22},{"name":"Mike","age":30}]}

Answer 9

Answer №5

Using Lodash for a solution

var keys = _.head(request.student);
var valueGroups = _.flatten(_.zip(_.tail(request.student)));

var studentObjects = valueGroups.map(function(values){
    return values.reduce(function(obj, value, index){
        obj[keys[index]] = value;
    return obj;
  }, {});
});

console.log(studentObjects);

Check out the code on JsFiddle: https://jsfiddle.net/

Answer 10

Using Lodash for a solution

var keys = _.head(request.student);
var valueGroups = _.flatten(_.zip(_.tail(request.student)));

var studentObjects = valueGroups.map(function(values){
    return values.reduce(function(obj, value, index){
        obj[keys[index]] = value;
    return obj;
  }, {});
});

console.log(studentObjects);

Check out the code on JsFiddle: https://jsfiddle.net/

Answer 11

Answer №6

Here is a straightforward solution using Javascript:

 var data =  {
      "students": [
        [
          "name",
          "age"
        ],
        [
          "Tom",
          12
        ],
        [
          "Jack",
          13
        ]
      ]
    };

var allStudents = [];
for(var i = 1; i < data.students.length; i++)
{
  var studentObj = { 'name' : data.students[i][0],
               'age' : data.students[i][1]
             }
    allStudents.push(studentObj);
}
data = { 'allStudents' : allStudents}

console.log(data);

Answer 12

Here is a straightforward solution using Javascript:

 var data =  {
      "students": [
        [
          "name",
          "age"
        ],
        [
          "Tom",
          12
        ],
        [
          "Jack",
          13
        ]
      ]
    };

var allStudents = [];
for(var i = 1; i < data.students.length; i++)
{
  var studentObj = { 'name' : data.students[i][0],
               'age' : data.students[i][1]
             }
    allStudents.push(studentObj);
}
data = { 'allStudents' : allStudents}

console.log(data);

Formatting Arrays of Objects

Answer №1

Answer №2

Answer №3

Correcting your initial code snippet

Answer №4

Answer №5

Answer №6

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