Learn
Great job — we just covered a lot of LINQ! Here’s a recap:
- LINQ is a set of language and framework features for writing structured, type-safe queries over local object collections and remote data sources.
- Use LINQ by referencing the
System.Linq
namespace in your file. - When a LINQ query returns a sequence of elements its type is
IEnumerable<T>
. That means it works withforeach
loops and its length is accessible withCount()
. - Store a query’s result in a variable of type
var
.var
is an implicit type, meaning it gets all of the benefits of type-checking without our specifying the actual type. - LINQ queries can be written in method syntax or query syntax.
- We prefer method syntax for single operations and query syntax for most everything else.
- The
Where
operator is used to select certain elements from a sequence. - The
Select
operator determines what is returned for each element in the sequence. - The
from
operator declares a range variable that is used to traverse the sequence. - LINQ can be used on arrays and lists, among other datatypes.
If you’re curious or want more practice, here are some additional resources:
- Learn more by reading Microsoft’s guide to LINQ.
- Find a list of keywords for query syntax here.
- Find a list of common methods for method syntax here.
- Find a complete list of methods for
IEnumerable<T>
here.
Instructions
1.
There are a few bugs in this code! Fix each one before moving on.
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