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Why IEnumerable is faster than list?
Why? Because you can still pass the list to the function if you want — A list is an IEnumerable. For that matter, so is an array and many other collection types are well. So by using an IEnumerable here, you take the exact same function and make it more powerful, because it can act on more different kinds of data.
Where is IQueryable used?
IQueryable uses Expression objects that result in the query being executed only when the application requests an enumeration. Use IQueryable when you have to run ad-hoc queries against data source like LinQ to SQL Server,Entity framework and other sources which implement IQueryable.
What is mean IEnumerable?
IEnumerable is an interface defining a single method GetEnumerator() that returns an IEnumerator interface. This works for read-only access to a collection that implements that IEnumerable can be used with a foreach statement.
Why do you use IEnumerable instead of list?
The last and final advantage to using IEnumerable over List is that by using the IEnumerable type, you are programming to an interface and not an implementation. This decreases the coupling on the collection underneath and provides a better way to manage collections of data.
When to use icollection, IList, list and IEnumerable?
Since in object oriented design you want to depend on abstractions instead of implementations, you should never have a member of your own implementations with the concrete type List/List.
What’s the difference between tolist and IEnumerable in Java?
IEnumerable describes behavior, while List is an implementation of that behavior. When you use IEnumerable, you give the compiler a chance to defer work until later, possibly optimizing along the way. If you use ToList() you force the compiler to reify the results right away.
How does the IEnumerable in a foreach work?
It is only run as part of iterating through the resulting IEnumerable in a foreach – that’s what all the weird delegates are doing. So, the first example evaluates the query immediately by calling ToList and putting the query results in a list.