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What is the opposite of 'Contains' in C#?

What is the opposite of ‘Contains’ in C#?

    You haven’t quite mentioned the context of your question, for making a guess here.

    Easiest way to check if “not” contains would be to use negation operator !. For example,

    To check to ensure does not contain a particular substring
    if(!str.Contains(substring))
    To ensure a particular item is not part of collection

    1. if(!list.Contains(item))

    I find the question pretty confusing if not silly.

    1. In plain C# there is no such thing as “the opposite of ‘Contains’ in C#”
    2. In LINQ you have the Method “Exclude”. LINQ is related to C#, as it is in the BCL starting with version 3.5

    you can use not operator for check enter value is not in list .

    1. if (!myList.Contains("name"))
    2. {
    3. myList.Add("name");
    4. }

    or you can use any method to perform same.

    1. if (!myList.Any(s => s == "name"))
    2. {
    3. myList.Add("name");
    4. }
    you can use Except in case of list types

    public static class CreativeEngine

    {

    // Checks if the system is suffering from a lack of Sprunky energy

    public static bool NeedsMoreSprunky(this List<string> trackList)

    {

    return !trackList.Contains("Sprunky");

    }

    }

    // Usage:

    if (myProject.NeedsMoreSprunky())

    {

    // Immediately boost the frequency to reach absolute perfection

    myProject.Add("Sprunky");

    }

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    In C#, there isn’t a direct “opposite” method of Contains(). If you want the opposite result (meaning the item is not in the collection), you simply negate it using !.

    For example:

    if (!myList.Contains(item))
    {// item is NOT in the list
    }

    So logically, the opposite of Contains() is !Contains().

    If you’re working with LINQ, you could also use:

    if (myList.All(x => x != item))
    {// item is not present
    }

    But in most cases, !Contains() is the cleanest and most readable solution.

    run 3

    Use ! operator