Single quotation with a number when getting the type of IEnumerable

Question

I have an enumerable as follows:

IEnumerable<SomeObjectType> dataToImport;

At runtime I run the following code:

dataToImport.GetType().ToString()

So far so good. Checking results at runtime shows me something like the following :

System.Collections.Generic.List`1[SomeObjectType]

Can somebody tell me what that `1 means and where it is coming from? Should I expect this on all collections?

Answer 1

It's a placeholder for the first generic type argument. You should expect it on anything with a generic type.

Answer 2

The backtick(`) followed by a digit represent the number of generic arguments. For example List<T> has one generic argument hence `1