javascript
array-methods
Array Methods
The Array object, as with arrays in other programming languages, enables storing a collection of multiple items under a single variable name, and has members for performing common array operations.
- Array Length
- Array toString()
- Array pop()
- Array push()
- Array shift()
- Array unShift()
- Array concat()
- Array slice()
- Array splice()
Array Length
If you are having an arrays of items, and you want to know how many items there are, you can use .length
const name = ["Afghanistan", "America", "Japan", "Russia"];
console.log(name.length); // 4
Array toString()
It will convert an array to a string with comma separated.
const name = ["Afghanistan", "America", "Japan", "Russia"];
console.log(name.toString()); // Afghanistan,America,Japan,Russia
Array pop()
It will remove the last item from an array.
const name = ["Afghanistan", "America", "Japan", "Russia"];
console.log(name.pop()); // ["Afghanistan", "America", "Japan"]
Array push()
It will add many items to the ending of an array.
const name = ["Afghanistan", "America", "Japan", "Russia"];
console.log(name.push("Thailand", "Italia"));
// ["Afghanistan", "America", "Japan", "Russia", "Thailand", "Italia"];
Array shift()
It will remove the first item of an array.
const name = ["Afghanistan", "America", "Japan", "Russia"];
console.log(name.shift()); // ["America", "Japan", "Russia"]
Array unShift()
It will add many items to the beginning of an array.
const name = ["Afghanistan", "America", "Japan", "Russia"];
console.log(name.unShift("Thailand", "Italia"));
// ["Thailand", "Italia", "Afghanistan", "America", "Japan", "Russia"]
Array concat()
If we are having several arrays and we want to combine them together and make them into one array, we can use concat().
const group1 = ["Ali", "Alex", "Ahmad"];
const group2 = ["Bob", "Bobby", "Bonnie"];
const group3 = ["Connor", "Charlie"];
const groups = group1.concat(group2, group3);
// => ["Ali", "Alex", "Ahmad", "Bob", "Bobby", "Bonnie", "Connor", "Charlie"]
We can replace the position of each array by especifing them first.
const group1 = ["Ali", "Alex", "Ahmad"];
const group2 = ["Bob", "Bobby", "Bonnie"];
const group3 = ["Connor", "Charlie"];
const groups = group3.concat(group1, group2);
// => ["Connor", "Charlie", "Ali", "Alex", "Ahmad", "Bob", "Bobby", "Bonnie"]
Array slice()
You can use this method If you are looking to delete the first several items.
const name = ["Afghanistan", "America", "Japan", "Russia"];
console.log(name.slice(1)); // ["America", "Japan", "Russia"]
console.log(name.slice(2)); // ["Japan", "Russia"]
console.log(name.slice(3)); // ["Russia"]
console.log(name.slice(4)); // []
Array splice()
You can delete several items, find a position and add your items.
const name = ["Afghanistan", "America", "Japan", "Russia"];
console.log(name.splice(2, 0, "Italia")); // ["Afghanistan", "America", "Italia", "Japan", "Russia"]
- First parameter says a position that you can add your new items.
- Second parameter defines how many items should be removed.
- The rest parameter defines your new items.
const name = ["Afghanistan", "America", "Japan", "Russia"];
console.log(name.splice(2, 1, "Italia", "Thailand"));
// ["Afghanistan", "America", "Italia", "Thailand", "Russia"]