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JavaScript JavaScript Foundations Arrays Splice

Posted by Sebastian Velandia
Sebastian Velandia
24,676 Points

What is the difference between use .splice and myarray[index] for replace values inside array?

I this video Jim explains that you can replace values with the splice method like this:

my_array.splice(index, 1, "my replace");

But you can also do it just with

my_array[index] = "my replace";

My question is, what is the difference? maybe does it affects the performance? is one of those faster (optimized) or they are just the same thing and does not matter what you use for replace a value in an array?

Thanks for you help Sebastian

1 Answer

eck
eck
43,038 Points

In the example you gave both techniques do indeed provide the same result. I am not entirely sure, but I expect that my_array[index] = "my replace"; is the faster of the two options.

The main difference is that splice will actually return the value(s) removed from the array. Splice can also replace a larger number of values in an array with one line of code (no repeating "my_array[x] = y" for every new value)

It is also a versatile method that can be used for more than just replacing values.

Example:

var array = [1,2,3,4,5,6];

var removedValues = array.splice(2, 3, "a", "b", "c");

//array will now contains [ 1, 2, "a", "b", "c", 6 ]

//removedValues will contain [ 3, 4, 5 ]