Manipulate and edit an array using JavaScript

Question

Manipulate and edit an array using JavaScript

Currently, I am working on a project in Javascript that involves processing a .dat file containing various data related to English Soccer teams. After extracting a Json from the file, I converted it into an array as follows:

[{"team":"Arsenal","f":"79","a":"36"},
{"team":"Liverpool","f":"67","a":"30"},
...
{"team":"Leicester","f":"30","a":"64"}]

This array contains the names of different soccer teams along with two values: goals scored (F) and goals conceded (A). The task at hand is to parse this array and perform the following operations:

Calculate the difference between "a" and "f" for each team and add this value to the array;
Determine the team with the smallest difference between goals scored and conceded.

However, I am currently stuck and unsure how to proceed with these operations.

I have managed to write some code up to this point:

const myFrom = document.getElementById("myForm");
const datFile = document.getElementById("datFile");

function fileToArray(text) {
    ...
}

myForm.addEventListener("submit", function (e) {
    ...
});

<form id="myForm">
    <input type="file" id="datFile" accept=".dat" />
    <br />
    <input type="submit" value="Submit" />
</form>

Unfortunately, this is where I hit a roadblock in my progress.

javascript arrays json associative-array

Answer 1

Answer №1

For a cleaner writing approach, both of these operations can be combined to achieve the desired result:

Map function is used to calculate and add the absolute difference between two properties as a new property called d.

The Math.abs function is implemented to ensure that the calculated difference is always positive.

let teams = [{"team":"Arsenal","f":"79","a":"36"},
{"team":"Liverpool","f":"67","a":"30"},
{"team":"Manchester_U","f":"87","a":"45"},
{"team":"Newcastle","f":"74","a":"52"},
{"team":"Leeds","f":"53","a":"37"},
{"team":"Chelsea","f":"66","a":"38"},
{"team":"West_Ham","f":"48","a":"57"},
{"team":"Aston_Villa","f":"46","a":"47"},
{"team":"Tottenham","f":"49","a":"53"},
{"team":"Blackburn","f":"55","a":"51"},
{"team":"Southampton","f":"46","a":"54"},
{"team":"Middlesbrough","f":"35","a":"47"},
{"team":"Fulham","f":"36","a":"44"},
{"team":"Charlton","f":"38","a":"49"},
{"team":"Everton","f":"45","a":"57"},
{"team":"Bolton","f":"44","a":"62"},
{"team":"Sunderland","f":"29","a":"51"},
{"team":"Ipswich","f":"41","a":"64"},
{"team":"Derby","f":"33","a":"63"},
{"team":"Leicester","f":"30","a":"64"}];

teams.map((t) => t['d'] = Math.abs(t.f - t.a))

console.log(teams);

To identify the team with the lowest difference, you can utilize the following code snippet along with the reduce function:

    let teams = [{"team":"Arsenal","f":"79","a":"36"},
    {"team":"Liverpool","f":"67","a":"30"},
    {"team":"Manchester_U","f":"87","a":"45"},
    {"team":"Newcastle","f":"74","a":"52"},
    {"team":"Leeds","f":"53","a":"37"},
    {"team":"Chelsea","f":"66","a":"38"},
    {"team":"West_Ham","f":"48","a":"57"},
    {"team":"Aston_Villa","f":"46","a":"47"},
    {"team":"Tottenham","f":"49","a":"53"},
    {"team":"Blackburn","f":"55","a":"51"},
    {"team":"Southampton","f":"46","a":"54"},
    {"team":"Middlesbrough","f":"35","a":"47"},
    {"team":"Fulham","f":"36","a":"44"},
    {"team":"Charlton","f":"38","a":"49"},
    {"team":"Everton","f":"45","a":"57"},
    {"team":"Bolton","f":"44","a":"62"},
    {"team":"Sunderland","f":"29","a":"51"},
    {"team":"Ipswich","f":"41","a":"64"},
    {"team":"Derby","f":"33","a":"63"},
    {"team":"Leicester","f":"30","a":"64"}];
    teams.map((t) => t['d'] = Math.abs(t.f - t.a))
    
    // Identify the team with the lowest difference
    
    let result = teams.reduce((teamA,teamB) => teamA.d > teamB.d? teamB: teamA );

    console.log(result);

Answer 2

For a cleaner writing approach, both of these operations can be combined to achieve the desired result:

Map function is used to calculate and add the absolute difference between two properties as a new property called d.

The Math.abs function is implemented to ensure that the calculated difference is always positive.

let teams = [{"team":"Arsenal","f":"79","a":"36"},
{"team":"Liverpool","f":"67","a":"30"},
{"team":"Manchester_U","f":"87","a":"45"},
{"team":"Newcastle","f":"74","a":"52"},
{"team":"Leeds","f":"53","a":"37"},
{"team":"Chelsea","f":"66","a":"38"},
{"team":"West_Ham","f":"48","a":"57"},
{"team":"Aston_Villa","f":"46","a":"47"},
{"team":"Tottenham","f":"49","a":"53"},
{"team":"Blackburn","f":"55","a":"51"},
{"team":"Southampton","f":"46","a":"54"},
{"team":"Middlesbrough","f":"35","a":"47"},
{"team":"Fulham","f":"36","a":"44"},
{"team":"Charlton","f":"38","a":"49"},
{"team":"Everton","f":"45","a":"57"},
{"team":"Bolton","f":"44","a":"62"},
{"team":"Sunderland","f":"29","a":"51"},
{"team":"Ipswich","f":"41","a":"64"},
{"team":"Derby","f":"33","a":"63"},
{"team":"Leicester","f":"30","a":"64"}];

teams.map((t) => t['d'] = Math.abs(t.f - t.a))

console.log(teams);

To identify the team with the lowest difference, you can utilize the following code snippet along with the reduce function:

    let teams = [{"team":"Arsenal","f":"79","a":"36"},
    {"team":"Liverpool","f":"67","a":"30"},
    {"team":"Manchester_U","f":"87","a":"45"},
    {"team":"Newcastle","f":"74","a":"52"},
    {"team":"Leeds","f":"53","a":"37"},
    {"team":"Chelsea","f":"66","a":"38"},
    {"team":"West_Ham","f":"48","a":"57"},
    {"team":"Aston_Villa","f":"46","a":"47"},
    {"team":"Tottenham","f":"49","a":"53"},
    {"team":"Blackburn","f":"55","a":"51"},
    {"team":"Southampton","f":"46","a":"54"},
    {"team":"Middlesbrough","f":"35","a":"47"},
    {"team":"Fulham","f":"36","a":"44"},
    {"team":"Charlton","f":"38","a":"49"},
    {"team":"Everton","f":"45","a":"57"},
    {"team":"Bolton","f":"44","a":"62"},
    {"team":"Sunderland","f":"29","a":"51"},
    {"team":"Ipswich","f":"41","a":"64"},
    {"team":"Derby","f":"33","a":"63"},
    {"team":"Leicester","f":"30","a":"64"}];
    teams.map((t) => t['d'] = Math.abs(t.f - t.a))
    
    // Identify the team with the lowest difference
    
    let result = teams.reduce((teamA,teamB) => teamA.d > teamB.d? teamB: teamA );

    console.log(result);

Answer 3

Answer №2

One effective way to tackle this problem is by utilizing either a loop (like for...of) or employing array methods such as map for the first part and filter for the second.

Personally, I find using loops more favorable due to its readability and ease of debugging, allowing for the integration of both steps within a single loop. For example:

// Initialize with the first element then iterate through the array
let leastDiff = Math.abs(myArray[0].f - myArray[0].a);
let bestTeam = myArray[0].team;
for (let item of myArray) {
  item.diff = Math.abs(item.f - item.a);
  if (item.diff < leastDiff) {
    leastDiff = item.diff;
    bestTeam = item.team;
  }
}
console.log(`The team with the smallest goal difference is ${bestTeam} with a difference of ${leastDiff}`);

Answer 4

One effective way to tackle this problem is by utilizing either a loop (like for...of) or employing array methods such as map for the first part and filter for the second.

Personally, I find using loops more favorable due to its readability and ease of debugging, allowing for the integration of both steps within a single loop. For example:

// Initialize with the first element then iterate through the array
let leastDiff = Math.abs(myArray[0].f - myArray[0].a);
let bestTeam = myArray[0].team;
for (let item of myArray) {
  item.diff = Math.abs(item.f - item.a);
  if (item.diff < leastDiff) {
    leastDiff = item.diff;
    bestTeam = item.team;
  }
}
console.log(`The team with the smallest goal difference is ${bestTeam} with a difference of ${leastDiff}`);

Answer 5

Answer №3

To find the team with the smallest goal difference, you can use a combination of map and reduce:

const teams= [{"team":"Arsenal","f":"79","a":"36"}, {"team":"Liverpool","f":"67","a":"30"}, {"team":"Manchester_U","f":"87","a":"45"}, {"team":"Newcastle","f":"74","a":"52"}, {"team":"Leeds","f":"53","a":"37"}, {"team":"Chelsea","f":"66","a":"38"}, {"team":"West_Ham","f":"48","a":"57"}, {"team":"Aston_Villa","f":"46","a":"47"}, {"team":"Tottenham","f":"49","a":"53"}, {"team":"Blackburn","f":"55","a":"51"}, {"team":"Southampton","f":"46","a":"54"}, {"team":"Middlesbrough","f":"35","a":"47"}, {"team":"Fulham","f":"36","a":"44"}, {"team":"Charlton","f":"38","a":"49"}, {"team":"Everton","f":"45","a":"57"}, {"team":"Bolton","f":"44","a":"62"}, {"team":"Sunderland","f":"29","a":"51"}, {"team":"Ipswich","f":"41","a":"64"}, {"team":"Derby","f":"33","a":"63"}, {"team":"Leicester","f":"30","a":"64"}]

let diff=Infinity;
console.log(
  teams.map((t)=>(t.d=t.a-t.f, t))
  .reduce((a,c)=>Math.abs(c.d)<=diff?(diff=Math.abs(c.d), c.team): a,'')
);

Answer 6

To find the team with the smallest goal difference, you can use a combination of map and reduce:

const teams= [{"team":"Arsenal","f":"79","a":"36"}, {"team":"Liverpool","f":"67","a":"30"}, {"team":"Manchester_U","f":"87","a":"45"}, {"team":"Newcastle","f":"74","a":"52"}, {"team":"Leeds","f":"53","a":"37"}, {"team":"Chelsea","f":"66","a":"38"}, {"team":"West_Ham","f":"48","a":"57"}, {"team":"Aston_Villa","f":"46","a":"47"}, {"team":"Tottenham","f":"49","a":"53"}, {"team":"Blackburn","f":"55","a":"51"}, {"team":"Southampton","f":"46","a":"54"}, {"team":"Middlesbrough","f":"35","a":"47"}, {"team":"Fulham","f":"36","a":"44"}, {"team":"Charlton","f":"38","a":"49"}, {"team":"Everton","f":"45","a":"57"}, {"team":"Bolton","f":"44","a":"62"}, {"team":"Sunderland","f":"29","a":"51"}, {"team":"Ipswich","f":"41","a":"64"}, {"team":"Derby","f":"33","a":"63"}, {"team":"Leicester","f":"30","a":"64"}]

let diff=Infinity;
console.log(
  teams.map((t)=>(t.d=t.a-t.f, t))
  .reduce((a,c)=>Math.abs(c.d)<=diff?(diff=Math.abs(c.d), c.team): a,'')
);

Manipulate and edit an array using JavaScript

Answer №1

Answer №2

Answer №3

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