What are the benefits to using String[] over List<String>? [duplicate]

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Possible Duplicates:

c# array vs generic list

开发者_运维百科 Array versus List<T>: When to use which?

I understand that there are several benefits of using List<>. However, I was wondering what benefits might still exist for using arrays.

Thanks.

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You'll have a simple static structure to hold items rather than the overhead associated with a List (dynamic sizing, insertion logic, etc.).

In most cases though, those benefits are outweighed by the flexibility and adaptability of a List.

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One thing arrays have over lists is covariance.

    class Person { /* ... */}

    class Employee : Person {/* ... */}

    void DoStuff(List<Person> people) {/* ... */}

    void DoStuff(Person[] people) {/* ... */}

    void Blarg()
    {
        List<Employee> employeeList = new List<Employee>();
        // ...
        DoStuff(employeeList); // this does not compile

        int employeeCount = 10;
        Employee[] employeeArray = new Employee[employeeCount];
        // ...
        DoStuff(employeeArray); // this compiles
    }

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An array is simpler than a List, so there is less overhead. If you only need the capabilities of an array, there is no reason to use a List instead.

The array is the simplest form of collection, that most other collections use in some form. A List actually uses an array internally to hold it's items.

Whenever a language construct needs a light weight throw-away collection, it uses an array. For example this code:

string s = "Age = " + age.ToString() + ", sex = " + sex + ", location = " + location;

actually becomes this code behind the scene:

string s = String.Concat(new string[] {
  "Age = ",
  age.ToString(),
  ", sex = ",
  sex,
  ", location = ",
  location
});

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I would only use an array if your collection is immutable.

Edit: Immutable in a sense that your collection will not grow or shrink.

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Speed would be the main benefit, unless you start writing your own code to insert/remove items etc.

A List uses an array internally and just manages all of the things a list does for you internally.