Discovering a key based on a value stored in a JSON-containing associative array

Question

Discovering a key based on a value stored in a JSON-containing associative array

In my search, I have come across a few answers that are similar, but not quite what I need.

Within an array called SongList, which I will show with just 2 items for brevity, the first pair is a key and the second pair is some JSON data.

SongList={
    song_1:{title:"title of first song",artist:"the artist",mp3:"http://mysite/song1.mp3"},
    song_2:{title:"title of second song",artist:"the artist",mp3:"http://mysite/song2mp3"}
    ...
};

I am looking to retrieve the key (song_1 or song_2) based on the value of the title.

My plan is to iterate through a temporary array containing i items. Each item in this array should match a key in the SongList, and I will store these keys (song_1, song_2) in a final array.

javascript arrays

Answer 1

Answer №1

Your data is made up of nested objects, not an array. Employ the for in loop.

function getTitleIndex(title) {
    for (var item in MusicLibrary) {
        if (MusicLibrary[item].title === title) return item;
    }
    return false;
}

Implement the function like this:

getTitleIndex("The First Song"); //returns "song_1"
getTitleIndex("Not This One"); //returns false

Answer 2

Your data is made up of nested objects, not an array. Employ the for in loop.

function getTitleIndex(title) {
    for (var item in MusicLibrary) {
        if (MusicLibrary[item].title === title) return item;
    }
    return false;
}

Implement the function like this:

getTitleIndex("The First Song"); //returns "song_1"
getTitleIndex("Not This One"); //returns false

Answer 3

Answer №2

Let's take a look at this demonstration.

let heroes = {
 first: {name:"Batman", powerLevel:5},
 second: {name:"Spiderman", powerLevel:7},
 third: {name:"Ironman", powerLevel:9}
};

for (key in heroes) {
    if (heroes[key].name === "Ironman") {
         console.log ("Key = " + key);
    }
}

If you are seeking Ironman, the output will correctly indicate third.

Answer 4

Let's take a look at this demonstration.

let heroes = {
 first: {name:"Batman", powerLevel:5},
 second: {name:"Spiderman", powerLevel:7},
 third: {name:"Ironman", powerLevel:9}
};

for (key in heroes) {
    if (heroes[key].name === "Ironman") {
         console.log ("Key = " + key);
    }
}

If you are seeking Ironman, the output will correctly indicate third.

Answer 5

Answer №3

Gratitude to all for shedding light on my confusion regarding Arrays versus Objects, which was impeding my ability to search effectively. With the guidance provided here, I have managed to craft a solution that I am pleased to share:

(The question above outlines an object called SongList)

Below is the function I developed for saving the keys of the playlist within SongList:

$("#save_playlist_as_keys").click(function() {
var keys = []
for(var i=0; i<myPlaylist.playlist.length; i++){
   var playItem = (myPlaylist.playlist[i].title); //this retrieves the track names
   for (var k in SongList){
      if(SongList[k].title == playItem) keys.push(k);//this links track name to keys
    }
}
localStorage.setItem('storedKeys',keys); 
});

It appears to be fulfilling my current requirements.

Answer 6

Gratitude to all for shedding light on my confusion regarding Arrays versus Objects, which was impeding my ability to search effectively. With the guidance provided here, I have managed to craft a solution that I am pleased to share:

(The question above outlines an object called SongList)

Below is the function I developed for saving the keys of the playlist within SongList:

$("#save_playlist_as_keys").click(function() {
var keys = []
for(var i=0; i<myPlaylist.playlist.length; i++){
   var playItem = (myPlaylist.playlist[i].title); //this retrieves the track names
   for (var k in SongList){
      if(SongList[k].title == playItem) keys.push(k);//this links track name to keys
    }
}
localStorage.setItem('storedKeys',keys); 
});

It appears to be fulfilling my current requirements.

Discovering a key based on a value stored in a JSON-containing associative array

Answer №1

Answer №2

Answer №3

Similar questions

Locating a specific class element within a collection of buttons using JQuery

Consistent Failure: jQuery File Upload consistently aborts with the error message 'File upload aborted'

Encountering an unexpected issue with $urlMatcherFactory during an AngularJS service unit test

Angular: Discovering and retrieving all images within a div container

What is the best method for effortlessly inserting multiple images into a web form that are sourced from a database?

Encountering a problem with a Vue component error stating "Unable to convert undefined or null to object"

As I iterate through a MySQL array, JavaScript is able to manipulate the initial displayed data

Import the contents of a *.data file into a growing array of structures that can dynamically expand

Finding All Initial Table Cells in jQuery

Unlocking the Power of Transition: Effortlessly Submitting a Form Post

require a global function that accesses a variable inside it

Form containing no field names using the multipart/form-data format

What steps can I take to locate the Angular version within my project?

Using asynchronous file uploading with jQuery and ASP.NET for a seamless user experience

Tips for fixing flickering tables and bringing the scrollbar back to the top in your DataTable Forge viewer

The issue with ui-router failing to render the template in MVC5

Performing a $lookup operation across various collections for a nested output

Converting month names to uppercase with moment.js

Utilizing regular expressions to search through a .md file in JavaScript/TS and returning null

The Cordova Android app is experiencing issues with Ajax requests