javascript tutorial - [Solved-5 Solutions] Append something to an array - javascript - java script - javascript array
Problem:
How to append an object (such as a string or number) to an array in JavaScript?
Solution 1:
Use the push() function to append to an array:
// initialize array
var arr = [
"Hi",
"Hello",
"Bonjour"
];
// append new value to the array
arr.push("Hola");
console.log(arr);
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Will print
["Hi", "Hello", "Bonjour", "Hola"]
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Solution 2:
If you're only appending a single variable, then push()works just fine. If we need to append another array, use concat():
var ar1 = [1, 2, 3];
var ar2 = [4, 5, 6];
var ar3 = ar1.concat(ar2);
alert(ar1);
alert(ar2);
alert(ar3);
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Will spit out:
"1,2,3"
"4,5,6"
"1,2,3,4,5,6"
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The concat does not affect ar1 and ar2 unless reassigned, for example:
ar1 = ar1.concat(ar2);
alert(ar1);
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Will display:
"1,2,3,4,5,6"
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Solution 3:
- WE think it's worth mentioning that push can be called with multiple arguments, which will be appended to the array in order. For example:
var arr = ['first'];
arr.push('second', 'third');
console.log(arr); // ['first', 'second', 'third']
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As a result of this we can use push.apply to append an array to another array like so:
arr.push.apply(arr, ['forth', 'fifth']);
console.log(arr); // ['first', 'second', 'third', 'forth', 'fifth']
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Annotated ES5 apply anymore, like:
arr.push(...['fourth', 'fifth']);
console.log(arr) // ['first', 'second', 'third', 'fourth', 'fifth']
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Solution 4:
We can use push and apply function to append two arrays.
var array1 = [11, 32, 75];
var array2 = [99, 67, 34];
Array.prototype.push.apply(array1, array2);
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It will append array2 to array1. Now array1 contains [11, 32, 75, 99, 67, 34]. This code is much simpler than writing for loops to copy each and every items in the array.
Solution 5:
Use concat:
a = [1, 2, 3];
b = [3, 4, 5];
a = a.concat(b);
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a now contains all the elements, [1, 2, 3, 3, 4, 5].