Analysis of array sort and reverse usage in Javascript_javascript skills

The examples in this article describe the usage of array sort and reverse in Javascript. Share it with everyone for your reference. The specific analysis is as follows:

The

sort() method is used to sort the elements of an array.

reverse() reverses the order of the elements in the array

First let’s try the following code:

Copy code The code is as follows:

var values ​​= [1, 0, 5, 15, 10];
values.reverse();
console.log(values);

What will the output be:
[ 10, 15, 5, 0, 1 ]

reverse() is simply to reverse the array, so the next thing I want to complain about is sort()

Copy code The code is as follows:

var values ​​= [1, 0, 5, 15, 10];
values.sort();
console.log(values);

The output result of this function is actually:
[ 0, 1, 10, 15, 5 ]

What’s going on?

Actually, will use toString() transformation inside the sort() function, and String comparison is through ASCII, so if we need to sort, it is better to write a sort() ourselves.

Copy code The code is as follows:

var values ​​= [1, 0, 5, 15, 10];
function compare(value1, value2) {
If (value1 < value2) {
         return -1;
} else if (value1 > value2) {
Return 1;
} else {
         return 0;
}
}
values.sort(compare);
console.log(values);

If you swap -1 and 1, you can sort in reverse order.

Current output:
[ 0, 1, 5, 10, 15 ]

A simpler way to write it is to use return value2 - value1;

inside compare()

I hope this article will be helpful to everyone’s JavaScript programming design.