How to push variable a1, a2, a3, a4 values inside for loop array.
var a1 = 100, a2 = 400, a3 = 700, a4 = 800;
var arr= [];
for (var i = 1; i <= 4; i++) {
arr.push("a"+i);
}
alert(arr);
The result is a1,a2,a3,a4 instead of 100,400,700,800.
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It is not possible in this way. But have a look at this discussion maybe it fits in your contextJeroen Heier– Jeroen Heier2016-04-16 05:30:09 +00:00Commented Apr 16, 2016 at 5:30
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1the simple way is to make a array instead of a1,a2...Madhawa Priyashantha– Madhawa Priyashantha2016-04-16 05:31:52 +00:00Commented Apr 16, 2016 at 5:31
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4 Answers
Use Eval for the solution of the problem.
var a1 = 100, a2 = 400, a3 = 700, a4 = 800;
var arr= [];
for (var i = 1; i <= 4; i++) {
arr.push(eval("a"+i));
}
alert(arr);Hope this helps you.
1 Comment
NiCk Newman
But wait! Douglas Crockford says
eval is evil! /s :Dvar a1 = 100, a2 = 400, a3 = 700, a4 = 800;
var arr= [];
arr.push(a1,a2,a3,a4);
alert(arr);
2 Comments
Rakesh
your solution is fine for less numbers of variables. but i have more than 100 variable set, so not possible to push statically variables in array.
dhruv jadia
u have specified 4 vars thats why I provided this solution
You can do without eval by using a map store your variables.
var map = { a1: 100, a2: 400, a3: 700, a4: 800 };
var arr = [];
for (var i = 1; i <= 4; i++) {
arr.push(map["a" + i]);
}
console.log(arr);
3 Comments
Rakesh
whats the common difference btn map and eval. what should use in my app.
Daniel Kobe
eval should be avoided at all cost, most people will never consider using eval. It has bad performance and, while not in your case, is usually a security risk. Read more here stackoverflow.com/questions/197769/… . Use the map, its a valuable data structure.Daniel Kobe
A map simply "maps" a key to a value. In this case a key would be
a1 and the value 100. Now I can ask the map for a key and it will return a value. You can also access a1's value like so map.a1You could use the window object for accessing global variables.
var a1 = 100,
a2 = 400,
a3 = 700,
a4 = 800;
arr = [];
for (var i = 1; i <= 4; i++) {
arr.push(window['a' + i]);
}
document.write('<pre>' + JSON.stringify(arr, 0, 4) + '</pre>');