What is in lightning component and how to use in lightning components?.

What is <aura:iteration> in lightning component and how to use <aura:iteration> in lightning components?.

aura:iteration iterates over a collection of items and renders the body of the tag for each item.

Data changes in the collection are rerendered automatically on the page. aura:iteration supports iterations containing components that have server-side dependencies or that can be created exclusively on the client-side.

Example Using Data from a Server-Side Controller

This example shows a dynamic iteration that displays data from a standard Opportunity object when user clicks on the button.

Apex Class:

public with sharing class OpporutnityLightningController {

   

    @AuraEnabled

    public static List<Opportunity> getOpportunities(){

        List<Opportunity> opplist = [select id,Name from opportunity];

        return opplist;

    }

}

Lightning Opportunity Component : 

Opportunity Component Controller.JS

Opportunity component App:

Output : 

In this example i am giving basic idea of how to use <aura:iteration> with apex class.

for more details you can refer salesforce documentation.

https://developer.salesforce.com/docs/atlas.en-us.lightning.meta/lightning/ref_tag_iteration.htm

https://developer.salesforce.com/docs/atlas.en-us.lightning.meta/lightning/ref_tag_iteration.htm