Simplifying javascript using for loop with update array values

Question

var thisdata = $.jStorage.get(something);
var nameChi = "nameChi" + i;
var name = "name" + i;
var brought = "brought" + i;
var amount = "amount" + i;
var np = "np" + i;
var num = "num" + i;

Above is working code which I want to simplify. I tried to turn individual assignments into a for loop with the code below:

thisdata = $.jStorage.get(something);
var generateid = ['thisdata', 'nameChi', 'name', 'brought', 'amount', 'np', 'num']

for (var a in generateid){
    var generateid[a] = generateid[a] + i
}

However, this is not working. Can anyone help me to solve this? Thanks a lot!!

You can't create dynamic variables like that. Just assign the values to another array — Phil, Dec 29 '16 at 02:30
^^ as said.. you can't create a dynamic variable but you can create a object with dynamic property. That is a close one to what you are trying — Rajshekar Reddy, Dec 29 '16 at 02:30
There's lots of things at play here - using a for-in to iterate over an array, using the `var` keyword when trying to mutate that array, and a possible misunderstanding of when to use Objects. — Jack Guy, Dec 29 '16 at 02:31
Thanks for you guys comments!! @JochenBedersdorfer , actually i am using a noob way to get data from a json file (let's say data A & data B), and I try to make those data (A1, A2, A3, B1, B2, B3) viewable (bring them to front end). — Kevin, Dec 29 '16 at 02:38
@RobG OP is trying to assign variable identifiers to elements of an existing array. — guest271314, Dec 29 '16 at 02:48
@guest271314 kind of, the array is created already, I'm trying to take that array(s) and display them into my own html file. — Kevin, Dec 29 '16 at 02:49
@YuenKevin Are you simultaneously trying to create a variable identifier for each of the elements of the array? — guest271314, Dec 29 '16 at 02:50
This is what you should consider doing : https://jsfiddle.net/nikdtu/swb5vrnr/ — Nikhil Maheshwari, Dec 29 '16 at 02:51

akuhn · Answer 1 · 2016-12-29T02:32:54.627

2

Try this

var generateid = ['thisdata', 'nameChi', 'name', 'brought', 'amount', 'np', 'num']
generateid = generateid.map(each => each + i);

How does this work?

map create a new array with the result of function
each => each + i is an anonymous function that adds i to each element

edited Dec 29 '16 at 02:32

answered Dec 29 '16 at 02:31

akuhn

27,477
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1

Where does `i` come from? – Phil Dec 29 '16 at 02:33
1

Where ever it comes from in the example given in the question … – akuhn Dec 29 '16 at 02:33
@akuhn Fair call :) – Phil Dec 29 '16 at 02:34
1

The OP wants to be able to generate variable names dynamically and not update his array values .. you can sense that intent of OP if you look at his code – Rajshekar Reddy Dec 29 '16 at 02:40

score 0 · Accepted Answer · answered Dec 29 '16 at 02:36

0

You can use destructuring assignment, Array.prototype.map()

var generated = ["nameChi", "name", "brought", "amount", "np", "num"]
                .map((n /*,i*/) => n + i);
var [nameChi, name, brought, amount, np, num] = generated;

answered Dec 29 '16 at 02:36

guest271314

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score 0 · Answer 3 · answered Dec 29 '16 at 02:37

In your code the Index is the problem for the assignment, Use this following code for the usage,

var val;
var generateid = ['thisdata', 'nameChi', 'name', 'brought', 'amount', 'np', 'num'];
var index=0;
for (val of generateid ) {
    generateid [index]=val + "i"
}

How is works,

In every for loop index will be incremented, So you can find the insertion index using that index value.

score 0 · Answer 4 · answered Dec 29 '16 at 02:38

0

Try this it will work.

 var ids = ["thisdata", "nameChi", "name", "brought", "amount", "np", "num"];
 var generateid = {};
 for(var i = 0; i < ids.length; i++){ 
      generateid[ids[i]] = ids[i] + i; 
 }

answered Dec 29 '16 at 02:38

Anil Talla

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Simplifying javascript using for loop with update array values

4 Answers4