//Creating Map with account id as key and account record as value
Map<Id,Account> accountMap = new Map<Id,Account>([SELECT Id, Name, Site, Rating, AccountNumber From Account LIMIT 100]);
 
//Getting list of account using map.values method
List<account> accList = accountMap.values();
 
//Getting set of account Id's using map.keySet method
Set<Id> accIdSet = accountMap.keySet();
 
//Getting list of account Id's using list.addAll method
List<Id> accIdList.addAll(accIdSet);