Salesforce Platform Developer I Certification Guide

Iteration collections

A collection can be a collection of Set, List, or Map instances. The for loop is used to iterate the code in a structure when looping a collection of records.

When looping through a map with records, you always need to define which of the two values you want to iterate. Here is an example:

Map<Integer, String> mapNumbers = new Map<Integer, String>{    1 => 'One',    2 => 'Two',    3 => 'Three'};// Iteration over the indexes of the mapFor (Integer iNumber : mapNumbers.keySet()){  // the keyset()-function of a map returns a set of the keys from the map. This is always a set of objects, defined in the map. In this case 1, 2 and 3  ...}// iteration over the values of the mapFor (String sString : mapNumbers.values()){ // the values()-function ...