How to add to end of list only if value not found anywhere in for each loop in c#-CodePudding

I am iterating through a list of numbers. If the number is not located anywhere in the list I want to add it into the list. I have an issue with my code.

foreach(String id in TestObject.Tags.ToList())
{
    if (id.Equals(x))
    {
        break;
    }
    else
    {
        TestObject.Tags.Add(x.ToString());
    }
}

There is a problem with my code. For example if the "id" didn't equal x then it would add "x" to the list. However "x" maybe located in the list however the foreach has not reached that point yet.

How do I fix this to check the whole list and if the id is not located anywhere in the list then add "x"

CodePudding user response：

You should only add if you finished iterating, not on every iteration.

To do so just introduce a bool-flag that indicates if you found the item already. If you found it, you can imediately break off the loop, otherwise just continue iterating.

bool found = false;
foreach(String id in TestObject.Tags.ToList())
{
    if (id.Equals(x))
    {
        found = true;
        break;
    }
}
if(!found)
    TestObject.Tags.Add(x.ToString());

A shorter approach however is using IEnumerable<T>.Contains:

if(!TestObjects.Tags.Contains(x))
    TestObjects.Tags.Add(x);