JS - Adding arrays to an array with variable name manipulation using for

Question

So I have some arrays (in reality I have about 30-40):

var p1  = ["John", "bio", "john.png"];
var p2  = ["Kate", "bio", "kate.png"];
var p3  = ["Mary", "bio", "mary.png"];

which have the respective information for each person I want to use in my HTML.

I want to add each of these arrays to another array to have a final result of:

var people = [["John", "bio", "john.png"], 
              ["Kate", "bio", "kate.png"], 
              ["Mary", "bio", "mary.png"]];

Is there a way of adding all these p1 , p2, p3 arrays to the people array using a for loop?

I tried this:

for (var i = 1; i <= 30; i++) {
    var toPush = "p" + i;
    people.push(toPush);
}

But obviously this just creates and pushes strings into the array. How can I get around this?

Thanks!

Why are you not adding initializing them in a people array in the first place? var people = [["John", "bio", "john.jpg"], ["Kate", "bio", "kate.jpg"], etc]; — Brennan
– Brennan, Commented Jun 4, 2015 at 17:10
Just use people = [p1, p2, p3]. If you don't like to type out thirty different variable names, don't use 30 variables in the first place. — Bergi
– Bergi, Commented Jun 4, 2015 at 17:14

brso05 · Accepted Answer · 2015-06-04 17:11:24Z

3

You should start with a people array instead of creating individual variables for each array create your arrays like this:

var people = new Array();
people.push(["John", "bio", "john.png"]);
people.push(["Kate", "bio", "kate.png"]);

etc...

answered Jun 4, 2015 at 17:11

brso05

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2 Comments

jackweirdy Over a year ago

Personally, I’d use var people = []; over var people = new Array();

ybp Over a year ago

You're right, I didn't realize how pointless what I was doing was until I read this.. :D Thanks!

jignesh · Accepted Answer · 2015-06-04 17:34:55Z

0

function ArrayList()
{
  var people=[];
  people.push(["John", "bio", "john.png"]);
  people.push(["Kate", "bio", "kate.png"]);
  people.push(["Mary", "bio", "mary.png"]);

    for(var j=0;j<people.length;j++)
    {
        console.log( people[j] );
        alert(people[j]);
    }
}

http://jsfiddle.net/ys9jptsn/

answered Jun 4, 2015 at 17:34

jignesh

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Comments

Community · Accepted Answer · 2017-05-23 12:21:56Z

0

You can use javascript eval for this purpose but it's not recommended. For issues with eval() please see https://stackoverflow.com/a/86580/4810628

function l(){
  var p1 = ["John", "bio", "john.png"];
  var p2 = ["Kate", "bio", "kate.png"];
  var p3 = ["Mary", "bio", "mary.png"];



  var people = [
    ["John", "bio", "john.png"],
    ["Kate", "bio", "kate.png"],
    ["Mary", "bio", "mary.png"]
  ];
  alert("length before adding elements:"+people.length);

  for (i = 1; i <= 3; i++)

  {
    people.push(eval("p" + i));
  }

  alert("length after elements added:"+people.length);

}

<body onload="return l()">
  
  </body>

edited May 23, 2017 at 12:21

CommunityBot

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answered Jun 4, 2015 at 17:25

user786

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3 Comments

Cᴏʀʏ Over a year ago

Why is there jQuery code in this answer? No jquery tag is present on the question, it could be confusing to the poster. You're also using a dangerous eval here...

user786 Over a year ago

@Cᴏʀʏ thanks for the info. here it says it's open to injection stackoverflow.com/a/86580/4810628 can you please add few words how an injection attack can happen with eval?

Cᴏʀʏ Over a year ago

Honestly, for this trivial example, there's technically no danger, but as using it at all is generally frowned upon, it's better to opt for code that excludes it altogether.

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