CODEWITHSUNDEEP
c#
DaveL
DaveL

Reputation: 87

Finding an index in a list of generic objects with multiple conditions

If I have a class that looks like this:

class test
{
    public int ID { get; set; }
    public int OtherID { get; set; }
}

And makes a list of those objects:

private List<test> test = new List<test>();

If I wanna try to find an index in this I would write:

int index = test.FindIndex(item => item.ID == someIDvar);

But now I wonder if I can use this to make more than one condition without writing another function for it? Like if I want to check if ID matches with a var AND OtherID matches with another?

Upvotes: 0

Views: 1647

Answers (3)

Christos
Christos

Reputation: 53958

Try this one:

int index = test.FindIndex(item => item.ID == someIDvar && 
                                   item.OtherID == another);

In the above snippet we use the && operator. Using the above snippet you will get the index of the first element in the list called test, that has a specific ID and a specific OtherID.

Another approach would be this one:

// Get the first element that fulfills your criteria.
test element = test.Where((item => item.ID == someIDvar && 
                           item.OtherID == another)
                   .FirstOrDefault();

// Initialize the index.
int index = -1

// If the element isn't null get it's index.
if(element!=null)
    index = test.IndexOf(element)

For further documentation, please take a look here List.FindIndex Method (Predicate).

Upvotes: 2

decPL
decPL

Reputation: 5402

No reason why you can't make your predicate more complicated:

int index = test.FindIndex(item => item.ID == someIDvar
                                && item.OtherID == someOtherIDvar);

Upvotes: 0

Andrei
Andrei

Reputation: 56688

Literally with && (and) operator:

int index = test.FindIndex(item => item.ID == someIDvar
                                   && item.OtherID == otherIDvar);

Upvotes: 2

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