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
– Phil, Commented Dec 29, 2016 at 2:30
^^ 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
– Rajshekar Reddy, Commented Dec 29, 2016 at 2:30
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
– Jack Guy, Commented Dec 29, 2016 at 2:31
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
– Kevin, Commented Dec 29, 2016 at 2:38

akuhn · Accepted Answer · 2016-12-29 02:32:54Z

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, 2016 at 2:32

answered Dec 29, 2016 at 2:31

akuhn

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4 Comments

Phil Over a year ago

Where does i come from?

akuhn Over a year ago

Where ever it comes from in the example given in the question …

Phil Over a year ago

@akuhn Fair call :)

Rajshekar Reddy Over a year ago

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

guest271314 · Accepted Answer · 2016-12-29 02:36:56Z

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, 2016 at 2:36

guest271314

1

Comments

K.Suthagar · Accepted Answer · 2016-12-29 02:37:10Z

0

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.

answered Dec 29, 2016 at 2:37

K.Suthagar

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Comments

Anil Talla · Accepted Answer · 2016-12-29 02:38:45Z

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, 2016 at 2:38

Anil Talla

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