I have a Map<String,List> and I want to convert to Map<String,String> converting list to string.join(','). I tried this, but it only replicates one value
User u = new User(); List<User> userUpd = new List<User>(); Map<String,List<String>> usersMap = new Map<String,List<String>>(); for(String uMap : usersMap.keySet()){ u.Order__c = uMap; u.Values__c = string.join(usersMap.get(u.Order__c.trim().toLowerCase()),','); userUpd.add(u); } This is because you never create a new user in memory, so they all reference each other.
As a basic example:
User u = new User(); User u2 = u; u2.LastName = 'Fear'; System.debug(u.LastName); // Fear You need to create a new user for each iteration through the loop:
for(String uMap : usersMap.keySet()){ User u = new User(); u.Order__c = uMap; u.Values__c = string.join(usersMap.get(u.Order__c.trim().toLowerCase()),','); userUpd.add(u); } 